Sharelatex is now opensource: https://www.sharelatex.com/blog/2014/02/21/sharelatex-is-now-open-source.html; discussion on HN: https://news.ycombinator.com/item?id=7276263. They also now offer a ‘personal’ account which allows for unlimited projects + one collaborator.
The other big player in this area of collaborative online Latex document editing is https://www.writelatex.com/. I’ve generally found their web app to be a little bit heavier on the computer (particularly my poor old Thinkpad X60s), but more polished. You can directly open a Writelatex document from templates at http://www.
My Latex package of the day is ‘siunitx’. No more worrying about flipping and and out of math mode, thinking how best to write an Angstrom or degrees celsius, or forcing units to be in upright fonts. I wish I had known about this years ago!
http://ctan.org/pkg/siunitx
via a very specific google on how to set ‘um’ http://tex.stackexchange.com/questions/522/best-way-to-typeset-micrometers