Copy edited. Used the official name of Stack Overflow - see section "Proper Use of the Stack Exchange Name" in <http://stackoverflow.com/legal/trademark-guidance> (the last section).

Copy edited. Used the official names of sites - see section "Proper Use of the Stack Exchange Name" in <http://stackoverflow.com/legal/trademark-guidance> (the last section).

Used the official name of Super User - see e.g. section "Proper Use of the Stack Exchange Name" in <http://stackoverflow.com/legal/trademark-guidance> (the last section).

(Space after full stop.)

(Ref. <http://en.wikipedia.org/wiki/Notepad%2B%2B>.)

Used the official name of the site (ref. <http://stackoverflow.com/legal/trademark-guidance> (the last section)).

added 4 characters in body

added 2 characters in body; edited title

Copy edited. Removed meta information (this is implied).

Used the official name of Super User - see section "Proper Use of the Stack Exchange Name" in <http://stackoverflow.com/legal/trademark-guidance> (the last section), etc.

Used the official name of Super User. (its = possessive, it's = "it is" or "it has". See for example <http://www.wikihow.com/Use-Its-and-It%27s>.)

A reference changed, etc.

Copy edited.

Copy edited (e.g. ref. <http://en.wikipedia.org/wiki/SQL> and <https://en.wiktionary.org/wiki/off-topic>).

Copy edited (e.g. ref. <https://en.wiktionary.org/wiki/upvote> and <https://en.wiktionary.org/wiki/someone#Pronoun>, ). Used the official name of Super User - see e.g. section "Proper Use of the Stack Exchange Name" in <http://stackoverflow.com/legal/trademark-guidance> (the last section).

Copy edited.