What is Microblogging?

Micro-blogging is posting of status updates, or short commentaries, on social networking. The size of the post is usually limited, in case of Twitter it is 140 characters.
Some on many social networks:
Google Buzz
Google, Facebook Places, FourSquare
MeetUp.com, EventBrite.com

Example Twitter post (tweet) 
"@UkiDLucas Thank you for organizing the great event on Mobile Technology Future! See full review at: http://bit.ly/fyhKUe #CyberWalkAbout" 

Uki's Google Java Technology blog