Twitter.

Facebook is where you lie to your friends, Twitter is where you are honest with strangers.

The thing to remember as with which website/blog service to use, is the relevancy of the social media format used.
Services such as twitter, due to their diary format and character restrictment are usually used as a place to post links to current work or in terms of participatory art request interaction.
For work such as mine where I am looking more for the work to be viewed in a method i determine, Twitter does not seem such a relevant option and although I can see it being invaluable for some artists practices, it is not, I feel, for me.

Above is my own Twitter Profile which I use to keep updated on the latest news following 'Tweeters' such as Guardian and BBC, and also to learn of current exhibitions and happenings in the art world using users such as...
Creative Review - which also prompts you to featured articles within the latest issue, which allows you to get up to speed without forking out for the magazine itself.
Dig Yorkshire - Is particularly good for keeping up to date with the latest events around the county and I have found out about many opportunities this way.
Vice - whilst sometimes cringe worthy in it's opinions, does host links to some relevant artists.