Advice on finding a subtenant

We are a network management/monitoring company based in San Francisco.  We occupy the 6th floor of a building in the financial/SOMA district and being a startup, we didn't need the entire floor.  So in August 2007, we put ads on Craigslist and Loopnet.  We ended up being contacted by a realtor, who was great to work with, and we sublet the space for a year.  Our tenants were a startup as well, and soon realized that they were growing and needed space of their own.  So back to Craigslist and Loopnet we went.  A co-worker had seen an article in TechCrunch about Rofo so we posted on their site as well.  What was great (and what differentiated them) about the Rofo site was the look, feel and content.  We received responses/inquiries from Craigslist and Rofo and ended up subletting our space to yet another startup!