Twitter can be extremely useful for many reasons. It can be a waste of time. It can be a fun waste of time!
My favourite hashtag this week is #scishirt. People post selfies of their science-themed T shirts. Some have institution's logos, often re-worked to get some effect. Some are funny. Some make you think, Oh God that's way over my head. But it's great to see how scientists are into their science.
Here's one for justifying slacking in the lab: