Prosper seems to be going through the same process Lending Club went through a few months back. Both are peer to peer lending sites where an individual can apply for a loan that is funded by other individuals, not banks. My understanding of the quiet periods is that both work(ed) to obtain the ability to give promissory notes. So instead of lending $25 to Joe, you're investing in a $25 note, applied to Joe's loan. Lending club went "quiet" on the lending/investing side in April and came back last week. I haven't gotten an email from Propser, but when I poked around my account today I fount the message.
I started investing with Lending Club (LC) early this year. I opened accounts with both, but the buy in for LC is only $25 where it's $50 at Prosper. In total I've lent $175 using both sites, from March to September. I've gotten back $20.24, which considering that the loan periods are 3 years, I'm happy with. None of my lenders have missed a payment (crossed fingers).
Now that LC is back, and Prosper is quiet, I'll shift any P2P investing back to LC. When Prosper is back I'll probably go back and forth between the the two.