you can compose a video comprising features or highlighted stuffs of your site (something like an ad) then post the same on popular sites like youtube and so on..
it really helps..trust me my friend got 50+ registered users for his forum in a single day after posting a spl stuff on a premier streaming site..
Who cares what youtube think, as long as it is effective and generate traffic people will use it.huh.. guys do u think youtube is not aware of such techniques ? have u ever read wiki on youtube?
Youtube is completely aware of such techinques and they are considered as SPAM!
please go through this: *en.wikipedia.org/wiki/YouTube#Spamming
(please let the page to load completely, then u will be taken directly to spamming)