Researchers generate complete human X chromosome sequence
Some good comments in here that explain some of the issues, and solutions, of acquiring a full sequence of a chromosome.
From what I've been able to see on the Net, this is the tweet that first suggested using a hash and a symbolic name to group together tweets by subject.
I can remember, back in the day, using this and an external website to then search particular tags on Twitter. Sadly I forget the name of the website.