It would be swell tough if the user could enter a youtube or vimeo link and share that, last.fm doesnt have it all. :)
And another thing, when clicking on an band-name it would be nice if there where some link to the artists entry on rateyourmusic.com . I find it to be the best service for discovering all the nerdy stuff about bands(like members, boolegs, reviews etc etc.)
You can actually post a youtube link - see explanation in http://blog.blaster.fm/2011/getting-the-most-out-of-your-bla... - but at the moment it's a bit of an "advanced" feature.
Quickstart: Click on charts in the top menu. Insert random obscure genre, be shure to check "+ child genres " Click Show Chart and be amazed.
A neat feature would be when entering an artist and title a little button or something would appera. Pressing it would launch a popup or something where the search results from youtube would appear where you could also listen/watch and then select the relevant video.