Megan McArdle:

Take Zillow, for example. The real estate site noticed that McMansion Hell, a blog specializing in acerbic architectural commentary on modern developments, seemed to be using some Zillow images. Zillow didn’t like this; Zillow makes money by helping agents sell houses, not helping bloggers make fun of them. So Zillow sent a cease-and-desist letter to Kate Wagner, who runs the site, ordering her to take down the photos.
 
 Wagner took the site down. She also took to Twitter to beg for help. In short order, she had a lawyer from the Electronic Frontier Foundation, and also, a wave of social media outrage at her plight. That wave crashed over Zillow, whose apologists had to shamefacedly explain that they had not intended to force her to shutter McMansion Hell.
 
 Now I am not a lawyer. But people who are lawyers specializing in First Amendment jurisprudence seem to think that Zillow hasn’t a legal leg to stand on. While copyright does prevent people from simply reprinting images or words that another person has created, there are exceptions for “fair use,” including for the purposes of parody or commentary. Fair use is not an unlimited right to copy, but it seems pretty clear that making fun of the houses on Zillow falls within those limitations.
 
 But even if the law had been behind them, Zillow would have been wise to refrain. That’s because the internet creates something known as the “Streisand Effect.” In 2003, Barbra Streisand attempted to suppress publication of photographs of her Malibu beach home. Prior to this ill-fated effort to disappear them, almost no one had been aware that these photographs existed. Afterwards, everyone knew — and looked.