By Jay Garmon

Pandora or Slacker? Last.FM or Grooveshark? There is a host of free streaming music services on the Web, but which one has the best features to go with its giveaway price? We sound it out in this listeners guide.

There are a few basic features common to most of online music services. Usually you cant request a specific song or band, but you can request that one or both are part of your music mix. Rating songs will entice these services to play them more or less often, but you can only skip or ban so many songs per hour (usually about 3-4) before you violate the services play license and youre stuck with whatever music it gives you. Almost all of these services let you purchase MP3 versions of songs from Amazon and iTunes. Nearly all of them have display and audio ads, which you can ban by upgrading to a monthly subscription service. Most of the music services are available only in the United States or North America (due to licensing restrictions). Finally, virtually all of these services have iPhone and Blackberry mobile versions, with most of them appearing on Android as well. Beyond this feature set, its the unique differences that make or break an online music service. I detail the various flavors below.

Pandora

Pandora is arguably the most high-profile of the free online music services, and it bills itself as a "music discovery service" which is a nice way of saying "were going to play at least as many songs you havent heard before as we are tunes you know and love." It works like this: You create a Station on Pandora by requesting a song or artist, and Pandora builds a virtual radio station that plays works from -- and similar to -- that song or artist. It does so by matching your request against the approrpriate song analysis from the Music Genome Project. For example, request "Jump" from Van Halen and youll get lots of Van Halen and lots of mid-eighties electric guitar riffs from other artists (including solo stuff from Sammy Hagar and David Lee Roth). Sometimes this results in great discoveries of songs and bands; sometimes it just drives you crazy. The good news is you can "tune" these Stations by rating each song with a thumbs-up or thumbs-down. Thus, the more time you spend build a Pandora station, the more you should like it -- provided you have the patience.

Pandora also has a nice Quickmix feature that will play selections from all your stations, and there are some nice Artist Info pages below the fold on each page. Perhaps best of all, theres an Im Tired Of This feature that will ban a song for 30 days without exiling it from a station permanently; this quickly became my favorite Pandora trick. Unfortunately, I found Pandoras Flash-based player to be a memory hog that occasionally crashed my browser. Your mileage may vary. Also, Pandoras licenses are unusual and you may "lose" a version of a song over time -- there are a lot of live/alternate cuts on Pandora that seem to spontaneously supplant the traditional album versions.

Slacker

Slacker is like Pandora if Pandora was run by professional DJs. You select pre-designed stations based on musical genre -- like Classic Rock or Indie Hits -- or select stations based on specific artists. Youll hear pretuned mixes of songs in that genre or by that artist, but the station will also play tracks by similar groups. The result is a much more refined and radio-like experience than Pandora; youll discover less and recognize more. Slacker also has some very fine-grained preference options, so you can have any song youve favorited played more or less often, ramp up the mix of popular versus obscure artists, and outright ban artists or songs from any station. You can also build custom stations from the ground up by feeding in artists. Slacker is the easiest of all the services to "surf" between stations. Slacker also tells you which song is going to play next, so you can spend your limited hourly skips more wisely -- dont jump past a song youre just tired of to land on a song you hate. Slackers premium version allows unlimited skips, displays song lyrics, and permits song requests along with removing its ads. Strangely, Slacker doesnt allow MP3 downloads of songs, but it will sell ringtone versions of most tracks.

Last.FM

Last.FM is a bit like Slacker in that it has stations based on artists, but it differs from the other services in that it boasts "instant" knowledge of your listening habits -- provided you regularly listen to MP3s on your PC. By downloading the Last.FM "Scrobbler" plug-in, the service integrates with iTunes, WinAmp and Windows Media Player and analyzes not just the songs already in your MP3 library, but the frequency with which you listen to them. From this observation Last.FM builds a preference profile for you and plays songs from its library matched to your tastes. You can also manually tune the suggestions without the Scrobbler, which will appeal to those who dont want the Scrobbler hanging out in their System Tray (where it can launch a browser-free Last.FM miniplayer). Last.FM also offers nice integrated song "sharing" -- as in "Hey, Im listening to this song!" announcements -- thanks to keen Facebook and Twitter integration. Beyond the usual Amazon and iTunes MP3 purchase options, Last.FM also links to 7Digital and offers ringtone purchasing. Last.FM is available in several European countries as well as the US, but manages its international licensing with somewhat aggressive IP address and cookie scanning. This same tech is used to promote live concerts and music events in your area, so if the artist youre listening to is playing a show nearby, youll be informed.

Grooveshark

Grooveshark, frankly, was the most impressive music service we came across, and probably will remain so right up until the moment its sued into oblivion. Unlike every other service weve seen, Grooveshark lets you request specific songs, build specific playlists, infinitely skip over any suggested songs, and fast-forward through songs by advancing the progress bar. Its basically a Web-based version of your iTunes account, but with access to thousands of other users iTunes libraries, too. Hows it work? Grooveshark doesnt "own" any music, it just lets users share. All the music in the Grooveshark library was uploaded by users, which leads to a highly diverse catalogue of songs that arent subject to Internet radio restrictions because they arent being "broadcast," theyre just being "shared" on a one-off basis between friends -- sort of like if I played you a record in my living room. Moreover, you can upload your own entire library (using a rather kludgy widget) to the service, so all your music is available online, anywhere in the world. You can also create embeddable widgets of a given song to play on your blog or Facebook page, which is a step beyond the typical Facebook and Twitter sharing options (which Grooveshark has, too). Download any Grooveshark song from Amazon, iTunes or as a ringtone. Groovesharks Radio feature suggests new songs based on whats already in your library, and it has a nice set of pop-up user tips that make tuning easy. The service is supported by unobtrusive sidebar ads, all of which go away with the Grooveshark VIP subscription service. I couldnt figure out what the library size limit is for standard Grooveshark users, but presumably its lower than the 50,000-song library youre allowed under Grooveshark VIP.

Live365

Live365 is the black sheep of online music services because its not actually an online music service; its an Internet radio station network. Search for a band or genre on Live365 and youll get a list of Internet radio stations -- run by real human beings and supported by commercials, just like broadcast radio stations -- that play those genres or artists. A number of actual, conventional broadcast stations actually use the Live365 service to stream their broadcasts over the Web. Live365 is a station-discovery service, not a music-discovery service. Users can build a list of "presets," like stored stations on an old-school car radio, and you can donate to stations with subscriber packages. If theres a station or list of stations you really enjoy, Live365 can generate embeddable widgets to install either lineup on your blog. While the quality of its stations is often quite good, the Live365 user interface is clunky and dated. If youre into it, Live365 offers services for setting up your own Web radio station. All stations have playlists of music that was recently broadcast, and these lists include Amazon and iTunes MP3 purchase links. I think of Live365 as a Web-based universe of niche/college radio stations -- but with lots more commercials.

The IdeaPad S10-2 is the latest generation 10" netbook from Lenovo, offering the 1.6GHz N270 Intel Atom processor and a 6-cell extended battery. Lenovo redesigned this netbook to make it look slimmer and more attractive than its predecessor, giving the edges a rounded look and a more modern appearance. In our review we see how well the IdeaPad S10-2 performs in our tests, to help you make an informed buying decision.

Lenovo went with an extended battery that significantly improves runtime over the smaller flush-mount one. The downside to this is it sticks out the back, and raises the netbook up off a surface about 0.75". Some could argue that it moves the keyboard into a more comfortable typing position, or it works great as an extra handle. I would personally like one that just sticks straight out the back, making aftermarket carrying cases much easier to choose.

Build quality is very good, with firm plastic used throughout the chassis and very little obvious flex or squeaking when you are carrying the netbook around. The screen hinges feel solid, needing two hands to easily open up the display. The matte plastic finish on the inside and bottom of the notebook stayed scratch free throughout the review. Likewise, the glossy finish held up surprisingly well; it did, however, give us a few scares, making us think we created huge scratches... which turned out to be smudges. Even if you did scratch this model, the black finish hides most blemishes (including smudges and dust).

From an upgrade standpoint Lenovo really wins our hearts with its user-friendly design that puts every swappable component behind one of two removable panels. Under the main panel, we have access to the hard drive, wireless card, and spare mini-PCIe slot with the connector included (some dont solder this in place so they can save money). The other slot is for the system memory, which is expandable to 2GB total. The only thing that could have made this better is if they went with the HP Mini approach, which doesnt even need a screwdriver to open the RAM cover.

The speakers on the S10-2 are lap-firing, facing down underneath the palmrest. If you are listening to the speakers on a flat desk surface you can hear the full (albeit limited) range of the speakers, but if the notebook is sitting on a soft surface like your bed or lap, they get quite muffled. Music from the speakers sounds clear and crisp with excellent higher frequency reproduction, but falls flat with midrange and low-frequency support. For VOIP, streaming music, or YouTube they will probably work fine, but headphones would be the best option if you plan on watching a movie or are doing something that requires you to pay attention to all the little nuances of the audio source.

The touchpad is a Synaptics model with limited multi-touch support. The only multi-finger control you get in the control panel is "pinch", to zoom in on the cursor area. Just the same, sensitivity and speed were excellent, with no lag present in our testing. The size of the touchpad could be slightly larger or wider, to give a more defined scroll region. The surface texture is a smooth, almost gloss finish, which has decent traction but still lets a sweaty finger glide across the surface without sticking.

Normally, users buying a netbook (outside of the ASUS N10 with dedicated graphics) understand that gaming just isnt going to be realistic. For this reason we find 3D benchmarks, which normally register very slow performance, to not be as relevant for these systems. Thus, we are shifting toward HD movie tests for netbooks, which are more in the realm of what a netbook can handle on the high end in terms of performance. In our HD video test the S10-2 played up to 480p and 720p video without much trouble. 720p video was starting to task the processor leaving little overhead, but it was very watchable. However, 1080p video was badly out of sync and painful to view.

In our ongoing quest to provide helpful information to our readers we are adding the following video playback table to our reviews of netbooks. Since netbooks are starting to be used for mobile entertainment (watching movie trailers or streaming video) its important to know how a netbook performs when trying to play a simple video file. We selected a family-friendly movie trailer and downloaded three different versions in 480p, 720p, and 1080p resolutions. We used the CCCP Codec Pack for decoding and Media Player Classic Homecinema (version 1.1.796.0) for playing all of the video files.