Internet company Yahoo announced without explanation it will close Yahoo Mash in Sept. 29. The one-year old service permitted users to create profiles of friends and use “modules” in a manner akin to Facebook.

In 2007, Yahoo killed Mixd, an attempt at mobile social-networking that lived only a few months.

Google last year introduced “OpenSocial,” a project to bring social-networking beyond just MySpace and Facebook by allowing any Web site to offer social-networking features.