SAN FRANCISCO - Facebook.com is getting a facelift designed to make the popular website's social networking features easier to find and use.

The makeover being announced Wednesday represents Facebook's most extensive overhaul in 18 months, said Mark Zuckerberg, the site's 22-year-old founder.

Besides adopting a new look, Facebook is introducing tools that will enable its users to learn more about their social networks and more easily conduct electronic conversations among multiple people simultaneously.

The Palo Alto-based website is the second largest social networking site behind MySpace.com, which was sold to News Corp. in 2005 for US$580 million.

Facebook last year spurned a $1 billion takeover offer from Yahoo Inc. and could attract even more tantalizing bids if Zuckerberg realizes his goal of doubling the site's audience during the next six months. Facebook currently has about 19 million active users, a number that has been rising by an average of 3 percent each week.

Despite Facebook's success, Zuckerberg said he and his team are constantly looking for ways to make it simpler to navigate around the site. ''There's always room for improvement,'' said Zuckerberg, who dropped out of Harvard University in 2004 to focus on building Facebook.

Change hasn't always been welcomed by Facebook's users. Last September, Facebook had to fend off a user rebellion after introducing a feature that made it easier to track revisions made to the personal profiles set up on the website. Thousands of Facebook users protested, arguing the change represented an invasion of privacy.

To minimize the chances of a backlash this time, Facebook tested its new look and features with more than 100,000 users.

Originally a hangout catering exclusively to college students, Facebook has branched out to other segments of society. The site, owned by Palo Alto-based Facebook Inc., now has more than 47,000 networks bound together by common employers and other shared interests.

Less than half of Facebook's users are currently in college, Zuckerberg said.