This recent episode of the TalkNerdy podcast goes a little into the problems behind TMO's unreliability. Namely recently graduated journalism students are made to write an average of 6 articles a day; leaving little time for fact/source checking advertisements-masquerading-as-press-releases from public relations firms.
Wikipedia itself should never be cited as a source; however, there are articles that are well sourced, and those can be valuable leaping off points.