In a development that shows how users can take Web 2.0 sites in unexpected directions, a group of Barack Obama supporters is using his presidential campaign's official social network to protest the Illinois senator's stance on a bill extending the so-called warrantless wiretapping program.

The social networking group set up on the MyBarackObama.com site to urge Obama to vote against the extension of the Foreign Intelligence Surveillance Act (FISA) had attracted more than 24,000 member entries as of last Friday, although some of the entries appeared to be duplicates.

"It's now a truism," wrote TechPresident.com blogger Patrick Ruffini, "that when presented with an open platform, users will hack it to serve their purposes, not necessarily those of the sponsor."

In a blog post of his own, Obama acknowledged that he is "not exempt" from efforts by voters to join together and "hold their leaders accountable." Despite the online protest, though, Obama voted for the FISA bill when it was approved by the Senate last Wednesday.