The author points out a trend that there are more garage sale postings on Craigslist this year, but Craigslist usage growth should be a factor in his research.
Craigslist stops displaying posts after a month but that doesn't mean they delete them...unless they are the dumbest businessmen I've ever heard of. They've got terabytes of old data that they constantly mine. That's my guess anyway, I don't buy their "we're like a non profit" facade one bit. They are smart, savvy, and very tough competitors. Read their terms of service if you don't believe me.
