Facebook also introduced the hashtag, a few months ago.
After several years since the launch of twitter that has become known all over the world the use of these eichette, facebook also implements the hashtag to improve the profiling of its members.
A true declaration of war on profiling.
Here's an interesting article on the potential and the importance of the use of hashtags.
http://mashable.com/2013/07/11/marketers-experiment-with-facebooks-hashtags/
