Since Facebook introduced its Groups feature in October, 50 million Groups have been formed.  But until today, there has been no good way to message a small number of people.  Yesterday with the launch of a Send button, Facebook has changed all that. In addition to Send details below) new improvements include integration with Questions, the ability to upload photo albums and additional membership controls.

"A year ago, we launched the Like button, which gives you a quick way to share the things you find on the web with all your friends," Elliot Lynde, a Facebook Groups engineer, wrote in a blog post. "But there are times when you find something that you only want to share with a few specific people."

How Send Works:

It you are in a site with Send buttons installed and want to tell your roommates about a great  article that you only want to share with them, hit the new Send button and decide who to send it to: friends, groups or any email address. You can then add a message and send the page to friends’ inboxes or post it to a Group wall.

Starting today, the Send button will be available on over 50 high traffic websites including WSJ, HuffPo and Orbitz. Expect many more sites to add it in the coming days.