I've been using this music streaming service called Hype Machine for a little over 5 years now and my account and all the songs I've hearted ("liked") over the years is easily one of my top 5 online possessions. It's become a daily part of my life; the process discovering new music throughout the week is enhanced by always having one place where everything can be found. This is going to make me sound dated to any other hypem users (cue the old grandpa voice) but I remember when top songs on their popular page only had a couple hundred likes, now their #1 songs (such as the Odesza remix of Zhu's "Faded" mentioned below) routinely have 5,000+ likes.
It's free to join and they're not very obtrusive. You "pay" by having ads pop up all the time when you open your page as well as some tricky border ads; annoying but again, it's totally free, so it's worth it to me. I'm sure they also get some revenue from referring people to buy concert tickets on songkick.com (which I've done many times over the years).
Soon they'll have an official Android app and it'll only increase my use of the site I'm sure. They are pretty aware of their product niche but are always rolling out new features with an eye towards the future. One reason why I originally liked them is because their popular page had a shelf life of 3 days so it always kept recent hot songs coming through. Recently they rolled out the ability to create "lists" of different styles/energies of music, they are "Up", "Down" and "Weird". I'm still figuring out the feel of each but this is brilliant on both the customer's and the company's ends; I get to have a quick way to play a similarly styled playlist and Hype Machine gets users to crowdsource genre-definition of all their songs. Once again the wisdom of the crowds will prove to be very useful.
Check it out particularly if you enjoy electronic/techno/EDM/whatever you call it and indie, as those are primarily the genres I see represented. I suggest when you begin to regularly use it that you curate a followed list of some blogs that you see playing the specific type of music you enjoy at the moment. If the blog's new song isn't exactly your flavor, a lot of times there will be another song in the post that you will like.