Facebook has acquired FriendFeed, an online aggregator of Twitter feeds and other social media services, social-networking websites and blogs.

Facebook announced the acquisition on Monday but did not disclose financial terms. FriendFeed's 12 employees will continue in their jobs under Facebook while its four founders will hold senior positions on the site's engineering and product teams.

FriendFeed, based in Mountain View, Calif., is a popular service that allows users to build a customized stream of content from various websites and social-networking tools. The service lets users keep track of what their friends are posting on Facebook, Flickr, YouTube, Twitter and personal blogs. Users can access their personalized feed through their email or on their cellphone or embed it onto web pages they use regularly such as their Facebook, blog or Twitter sites.

The four founders of the service — Bret Taylor, Paul Buchheit, Jim Norris and Sanjeev Singh — are all former Google engineers who helped design services such as Gmail and Google Maps. They started FriendFeed in 2007. Buchheit is also credited with coining Google's "don't be evil" motto.

In a blog post on Monday, Taylor said FriendFeed would continue to operate normally while a full long-term integration with Facebook is worked out.

The move by Facebook is being seen by bloggers as a way to beef up the social-networking website's real-time capabilities, particularly as Twitter becomes more popular, and as a way to acquire the skills of FriendFeed's acclaimed founders.

"And so begins the next step in Facebook's assault on Twitter," wrote TechCrunch.