Pandora is a music streaming website with a difference - instead of picking what music you want to listen to, you tell Pandora what you like and, based on the type of music, it suggests musically similar tunes.
Unlike other streaming websites such as Last.fm, Pandora doesn't suggest music based on what other users' tastes. Instead, using the Music Genome Project, it analyzes the musical content of the song or artist you like and plays other music that shares some of the defining qualities.
In order to use Pandora, you must create an account. Also, and unfortunately, you must also be resident in the US. The registration process is free and simple and will take less than 2 minutes. Pandora help is based around a comprehensive FAQ, but email support is also available.
What makes Pandora interesting is its flexibility. You create stations based on one or several songs or artists. You can mix and match these stations, choosing to play from one or combining a few. If you want to add variety to a station, you can, with Pandora even making suggestions if you are stuck. If you don't like the music that Pandora has suggested, you say so, and likewise, if you do like it, Pandora will take that into consideration for future suggestions.
On the practical side, Pandora is as web 2.0 friendly as other web apps. You have a traditional user profile that you can customize as you would on a social network, the opportunity to contact other users who like the same kind of music and various sharing options. Crucially, however, you can completely ignore these elements if you're not interested.
If there are any weak points to the Pandora experience, it is that the advertising in the free version is quite intrusive. Also, if you're a person who is quite specific about what you do and don't want to listen to, Pandora probably doesn't provide the control you'd want.
Pandora is a great streaming service for people who want to discover new songs and expand their musical horizons.