A Warning about Abilities that "Reveal" Targets
This is a quick post about abilities that "reveal" targets.
Currently, there is lack of clarity on what this actually means. There are several abilities that are stated to "reveal" targets, but this does not necessarily mean what you might think it does.
For example, Diana's Crescent Strike (Q), Lee Sin's Sonic Wave (Q) and Tempest (E), Kog'Maw's Living Artillery (R), and Warwick's Blood Scent (E), all have tooltips that state they reveal targets that are hit.
But there is a massive difference between Lee Sin's abilities and everyone else's. Namely, Lee Sin's abilities remove stealth temporarily, while the others do not.
What this means is that Diana, Kog'Maw, and Warwick are able to reveal targets through the fog of war, but if the target is capable of stealth, even if they hit it with a "revealing" abilitiy, that target will remain unseen.
According to this Riot post the wording/clarity problem has been noted and may be fixed in the future: http://na.leagueoflegends.com/board/showthread.php?p=28279960#post28279960
Conclusion: Very few abilities actually remove stealth temporarily. Many simply reveal through fog of war only.