I am using both ubuntu and elementaryOS. The latter has a community that is active most on irc and google plus, so that, after a while, it is very hard to keep track of the problems and answers. That community is not very active on stackexchange, although it is welcome.
So, I would like to post here some of the main questions that I was confronted with in order to provide answers that would be easy to track by me and others.
(It is ok to do this on askubuntu - here.)