If your not using StumbleUpon, then your missing out on a ton of free traffic. Just google that and you can get a addon for your browser. Build up your social account buy stumbling a lot of pages, adding some friends, filling out your profile, making comments, etc. and then stumble a few of your pages once in a while and you could see some nice traffic bursts. Last summer, on a video site I had, I managed to pull a good 1-5K unique visitors a day for over a month off of StumbleUpon. I also highly recommend that you put a StumbleUponbutton on each on of your pages so your users can vote for your page. The best thing about StumbleUponis a lot of times the users will post your link elsewhere and that really helps with SEO. Something to check out is
AutoStumble | Home, it costs around $40 but is worth it if you have good, viral content (maybe a unique or new flash game). I managed to buy it when it was only $20, and so far I'm pretty happy with my investment.
Here is a review on the program if your considering it.