R - The statistical exploration language

I don't know why I've never posted anything about R - if you use statistics, use R - if you want good quality graphs use R.  R is available for all major platforms, allows you to use Bayesian or classical methods, and has packages for most things that you might be interested in.  Easy to use, even easier if you use RStudio as an IDE.

Collaborative writing and LaTeX in the cloud revisited

Since I last commented on this there have been some changes. WriteLaTeX has relaunched as Overleaf.  It now emphasizes online collaboration using rich text - though you can still work directly in LaTeX if you prefer.  There is still a free version.

As to the others ShareLaTeX still offers free personal accounts, but is more expensive than Overleaf for paid accounts (there is a good discount for students.)  ScribTeX seems to no longer exist, the website has a redirect to a ShareLaTeX page - but the page no longer exists. Verbosus is still an ongoing project, I've used it on my mobile devices.

Other entrants to this market include Papeeria and Authorea, I am sure that there are others.  All are useful and have free options - but there is no substitute for having a full TeX Live distribution on your own computer.