Tweetup
What it means: Tweetup is an organised or impromptu 'meeting' between people who are on Twitter. Cash in on Limited Liability
Origin: The word became popular in business circles recently, and is mash of 'tweet + meet up'. The word has now been included in the Oxford Dictionary.
Usage: A tweetup is widely used to refer to what is now sometimes described as offline networking - an opportunity to meet people who might be useful contacts for developing your career and business interests