I did search and found nothing regarding this little hidden gem on Chase's Ultimate Rewards shopping mall.
2,500 UR points just for creating a new account on stamps.com. It is usually a paid service but there is a free 4 week trial and canceling is very easy.
I wrote about it in further detail on my blog. Hope this helps some people!
http://infamousdx.com/2011/09/05/free-2500ur/
UPDATE
How to cancel the account:
http://infamousdx.com/2011/09/10/cxl-stamps/