This really sucks and I don't know why I've been sandboxed or penalized. I can only hope that my site comes back soon as I keep adding content. I've slowed down a bit on the link building (although I never did it that fast). I think Google may think my cake site is too much of a thin affiliate site so I'm just adding more original text content to each party page. If you have any other ideas I'd love to hear them. Thanks!
I have been sandboxed before, it sucks but it will be removed in a matter of time. Just carry on regardless and continue to build content and links. Once you get out of the sandbox you will do well if you have continued in building content and links. I went from being sandboxed to first page of Google on a fairly competitive keyword in a very short space of time as I was continually working on the site regardless. All the best, I hope it works out well.
Don't put all your eggs in one basket. Web 2.0 stuff will always be a backup when Google isn't helping you for whatever reason.
It's a pretty made for adsense site. And MFA is not exactly rank worthy in the eyes of Google. So you have no other traffic sources then you are out of luck. Diversify or Die.