As a programmer, I am used to a vibrant documentation system with exhaustive references and tutorials online. Does such a system exist for Stata? Where do people go for quick stata questions (besides Cross Validated)? How did people here learn Stata?
Stata comes with extensive help files and full manuals in PDF, with hyperlinks from the help files to the relevant manual entry. The help files give the syntax and examples, with some notes on using the command, and have extensive hyperlink cross-references. The manuals explain the syntax, give examples of using the commands and interpreting the output, include the mathematical models being used when relevant, and give detailed references.
In addition, the source code for most of the commands (which are written in Stata's language) is easily viewed so you can see exactly what is being done.
There is also Statalist (http://www.stata.com/support/faqs/res/statalist.html), a very helpful email list.
Stata Press (http://www.stata-press.com/) publishes books on use of Stata or on areas of analysis with Stata as the software used.