It starts when you're young -- a friend's older brother hands you a
Fugazi tape and all of a sudden, you're hearing a sound that's totally
new.

Your friend's older brother has since been replaced by the web.
There's more great music that you've never heard out there than ever
before, but the veritable flood of material from artists of all
stripes has made finding those choice nuggets of bliss that much
harder.

Several websites offer a reprieve from this overabundance of noise
with a collaborative filtering process best described as "taste
matching." Sites such as Pandora, iLike, Last.fm and Qloud recommend
artists you might enjoy by comparing your favorite bands with those of
other users.

These sites assume that if you have a favorite band in common with
another user, then other artists on their list of favorites will most
likely also appeal to you. The results are far from perfect, but it
beats digging for audio gold at Google.

I tested all the sites in the same way, searching for bands similar to
Neutral Milk Hotel, Talib Kweli and Justin Timberlake.

Oddly, I found the more mainstream an artist is, the less precise your
results are likely to be. The recommended artists similar to Neutral
Milk Hotel, which is arguably the most left-field pick of the three,
were almost universally more accurate across all four services.

Pandora

The most enjoyable set of results came from Pandora, a service built
by the creators of the Music Genome Project.

Pandora is dead simple -- just type in a band you like, and it will
immediately begin streaming a playlist of music similar to the band or
artist you entered. The service explains why it recommends the songs
it picks for you.

You can only play the streaming playlists Pandora offers in a browser
window, but you can e-mail the stations to friends or share them on
personal websites. Pandora's service also has some helpful features,
like the ability to bookmark songs for later review and a search tool
called Backstage that tells you more -- biographies, discographies and
further recommendations -- about the artists you encounter.

iLike

I first encountered iLike when I reviewed it on the Monkey Bites blog.
The site is actually a full-featured social networking site centered
around music, but its integration with your computer's iTunes
playlists is what turns it into a powerful music discovery tool.

ILike adds a sidebar to Apple Computer's iTunes player and tracks your
listening habits. The service then matches your tastes with those of
other users and recommends similar artists from others' playlists that
you may enjoy. You can listen to streaming samples of the recommended
tracks and, in many cases, purchase them from the iTunes Music Store.
Songs by independent and unsigned artists can be streamed or
downloaded from GarageBand.com, iLike's partner site.

ITunes is the only media player supported by iLike, though the company
claims it's working on support for other players.

Last.fm

Last.fm is essentially a web-based, user-programmed radio station. It
studies your tastes through a desktop applet called Audioscrobbler.
The tiny application runs in the background, tracking your playlists
in iTunes and other popular players. It then streams a playlist made
up of songs by artists similar to the ones you like based on similar
tastes of other Last.fm users.

You can also listen to streams of user-recommended music in your
browser window using Last.fm's recently added, Flash-based player if
downloading desktop software isn't your bag.

Qloud

Qloud returned some good recommendations. However, the
JavaScript-heavy interface may turn some users off -- the fancy
features like auto-complete search suggestions come at the expense of
your browser's back button. Also, Qloud requires Windows Media Player
to play its song samples.

Summing Up

All these services give you new ground to explore, and your best bet
might be to use the one or two that offer the best suggestions within
your favorite genres. After all, when it comes to deciding how to
spend your hard-earned cash at the record store, recommendations come
in handy.