Twitter: Classic social networking site used by academics to post and share research. 'Likes' and 'shares' feed into analytics tools such as PlumX Analytics, which is embedded in Scopus.
Researchers in your discipline have a presence there and you want to make connections.
You want to share news about your work and publications to a broad audience.
You want to increase your alternative metrics counts (tweets about your work are tracked by PlumX Analytics and can therefore raise the visibility of your work).
You want to interact with others online who are interested in your work.
You are concerned about what Twitter will do with your personal information.
You are concerned about privacy.
You are concerned about online harassment and trolling.
You do not have the time to keep your Twitter feed fresh and up-to-date.