I keep my account open mainly for non-mainstream news and memes — i.e., reading what the judiciously few accounts I follow share, while only rarely participating myself. I keep my account open so I can indirectly support (follow) the few accounts that deserve it. Twitter can be useful, if used sparingly and wisely.
Best Twitter advice ever:
“Absorb what is useful, discard what is useless, and add what is specifically your own.”
–Bruce Lee