Website have been bouncing around for several days and weeks. (since easter) I would wait it out before jumping to conclusions.
if it's the one in you sig then I have no idea why it doesn't rank #1 I'm assuming it's not since that site simply says file upload with no other content
no it is a pr5 health site, when i search the site name nothing show up. i was checking the status of a few ranked keywords and all disappear. penalty i'd say i may as well wait and see
Have you incurred in some heavy link exchange?. Maybe lots of duplicate content?. Cloaking? Just follow google guidelines, if you didnt do anything that is written there then I have no idea why, all the sites I had that got penalized were because of heavy link exchange with other sites nothing else I guess its the main thing that affect Google's serps.
Could be a lot of factors man. Were changing your something in your metas? Mass Backlinking? Tell us some more. Hard to guess from the other side of the world
No, I have not noticed such issues though there does have some fluctuations on ranking for some of my targeted keywords. Thanks,
Are you serious ? How did you realise that its been penalised? Did you get any mail or they dont show any results on google when you type your site url. Let us know so we can also be aware of this situation if occur anytime