Andem - 11:33 pm on Jun 6, 2013 (gmt 0)
I guess I should add my $0.02:
I have a (content) site which has been live for 11 months now and I've seen increases in traffic every few weeks since the beginning which peaks, falls slightly by around 5-7% and then stabilizes until the next boost. The drop this time was a little delayed and a little more dramatic (~11%) and it happened on June 5th.
I don't know if this has anything to do with Penguin or Panda, but the site has a pretty thin backlink profile and I don't do any type promotion or backlink building at all. On the other hand, many of the backlinks that I have noticed are on non-English language forums and blog articles/howto articles to this English-language site.
I do have to admit that SERPs look a little bit off and they seem to be dancing.