In her 23researchthings post this time, Georgina looks at Reddit, Wikipedia and GitHub. I'd better leave GitHub out of the reckoning, as it is for sharing code, and I am not a coder.
Wikipedia I use every day, in the way Georgina and the other 23researchthings participants describe. My experience as a Wikipedia editor is very slight, and dates from 2008, but it did happen. I made some small modifications to the entry for the village in which I grew up, and described the experience in a poem. I can think of no instances since then where the urge to correct a Wikipedia entry has been so strong for me as to force such a use of time. However, the ancillary parts of the entries -- the references, and the 'Talk', 'Contributions', and 'View history' links -- are of obvious use to research.
I don't think I'd looked Reddit before tackling this Thing. I have now joined it, and posted my first question there. The site is indeed very clunky, and I didn't like the fact that new members are not only expected to join subreddits (roughly equivalent to Twitter's lists), but even have a number of these subreddits assigned to them on arrival.
A couple of hours after posting, my question has drawn no attention. Let me admit, however, that a shortened version of it has similarly drawn nothing on Twitter. Present company will probably have seen me air the question before, in my coursework for Thing 5, and are statistically unlikely to have now the answers they didn't have then.
It may be that Reddit, like Twitter, will reveal its merits to me after a few months of inactive membership. Meanwhile, I can see the point of it, and may suggest it to others who don't mind a bit of untidiness when asking oddball questions.