Once users opt for "web suicide" the process cannot be halted.
Social network giant Facebook has blocked a website from accessing people's profiles in order to delete their online presence.
The site, Web 2.0 Suicide Machine, offers to remove users from Facebook, Twitter, LinkedIn and Myspace.
It does not delete their accounts but changes the passwords and removes "friend" connections.
Seppukoo.com, which offers a similar service, was issued with a "cease and desist" letter by Facebook in 2009.
Netherlands-based moddr, behind Web 2.0 Suicide Machine, says it believes that "everyone should have the right to disconnect".
However Facebook says that by collecting login credentials, the site violates its Statement of Rights and Responsibilities (SRR).
"Facebook provides the ability for people who no longer want to use the site to either deactivate their account or delete it completely," the company said. "We're currently investigating and considering whether to take further action."
