This is a new term to me. It was used over on simra.net in reference to the attempt by students at Wilfred Laurier University to dictate to the Laurier Freethought Alliance [Follow-up on the WLU controversy]. I had to look up the term on Wikipedia.
Just in case there are any other old people out there, here's the definition.
The "Streisand effect" is a term used to describe a phenomenon on the Internet where an attempt to censor or remove (in particular, by the means of cease-and-desist letters) a certain piece of information (for example, a photograph, a file, or even a whole website) backfires. Instead of being suppressed, the information receives extensive publicity, often being widely mirrored across the Internet, or distributed on file-sharing networks in a short period of time. Mike Masnick said he jokingly coined the term in January 2005, “to describe [this] increasingly common phenomenon.” The effect is related to John Gilmore's observation that, "The Net interprets censorship as damage and routes around it."
The term Streisand effect originally referred to a 2003 incident in which Barbra Streisand sued photographer Kenneth Adelman and Pictopia.com for US$50 million in an attempt to have the aerial photo of her house removed from the publicly available collection of twelve thousand California coastline photographs, citing privacy concerns. Adelman claims he was photographing beachfront property to document coastal erosion as part of the California Coastal Records Project. Paul Rogers of the San Jose Mercury News later noted that the picture of Streisand’s house was popular on the Internet.