Pandora promises to "play only music you'll love," and that they do. Using information from its Music Genome Project – Pandora's own, continually updated music database. Simply sign up for a free account (no credit card information required), enter your favorite artist or song, and start listening to a station that features songs Pandora thinks you're likely to enjoy. You can give songs a "thumbs up" or "thumbs down" and "skip" songs you don't like. Pandora then stores all of this information to fine tune your listening experience with capacity for up to 100 unique stations.
Cost: Pandora is free, but if you want to listen without adverts, get Pandora One for $3.99 per month, or $36 per year.
Sharing: Pandora allows you to share songs and stations on Facebook and Twitter.
Limits: With the free Pandora account, you can only listen to 40 hours of music a week, a limit that applies both the smart phone app and web streaming. Plus, Pandora only has access to 1 million songs, versus over the 20 million that are offered by Spotify and others.
Devices: Accessible on PC and Mac via pandora.com. For mobile devices, you have to download the Pandora app.