If you missed this link last time, I endorse Empire Avenue as a way to lift your Social Networking / Social Media branding. Which, in turn, can provide backlinks to your SFI sign-up page.
SEO and Google's ranking has changed, now it's all about branding and your associations on the web.
Link yourself with reputable brands and people...
P.S. Also try -
XeeMe - http://xrl.co/inviteme
and my free classified - http://xrl.co/classifieds