What is the like for in the outline?

In the front page for each item, there is the "like" button.

For each group, a visitor can follow/join the group, but if the user liked the group there will be nothing added, like a counter or something.

What was the idea behind this like?

Thanks!

"Like" in Timeline is the same as 5 star voting.

So then user like a groups, it the same if user click 5 star voting in the group.

 thanks, AlexT