"What counts as name-calling? What counts as making fun of someone in a way that's good-natured?" said Jason Goldman, Twitter's director of program management. "There are sites that do employ teams of people that
do that investigation ... but we feel that's a job we wouldn't do well."
Other sites are trying to be more transparent in their decisions.
Online auctioneer eBay Inc., for instance, has elaborated on its policies over the years, to the extent that sellers can drill down to where they can ship hatching eggs (U.S. addresses only) and what items related to natural disasters are permissible (they must have "substantial social, artistic or political value"). Hypothetical examples accompany each policy.
LiveJournal has recently eased restrictions on blogging. The new harassment clause, for instance, expressly lets members state negative feelings or opinions about another, and parodies of public figures are now permitted despite a ban on impersonation. Restrictions on nudity specifically exempt non-sexualized art and breast feeding.
The site took the unusual step of soliciting community feedback and setting up an advisory board with prominent Internet scholars such as Danah Boyd and Lawrence Lessig and two user representatives elected in May.
The effort comes just a year after a crackdown on pedophilia backfired. LiveJournal suspended hundreds of blogs that dealt with child abuse and sexual violence, only to find many were actually fictional works or discussions meant to protect children. The company's chief executive issued a public apology.
Community backlash can restrain service providers, but as Internet companies continue to consolidate and Internet users spend more time using vendor-controlled platforms such as mobile devices or social-networking sites, the community's power to demand free speech and other rights diminishes.
Weinstein, the veteran computer scientist, said that as people congregate at fewer places, "if you're knocked off one of those, in a lot of ways you don't exist."