According to a report on Tom's Guide that is based on word from "an industry source" and is "corroborated by two additional sources", Bethesda Softworks will be blowing the lid off the always-suspected-but-never-confirmed MMO in development at ZeniMax, The Elder Scrolls Online, sometime in May. Apparently the MMO version will be set several hundred years before any of the previous single player TES titles, will feature three playable factions, and will likely make its first major public debut at this year's E3:
Elder Scrolls Online will have three playable factions, according to the tipster. Not much is known about the factions, except each is represented by one of three animals: A lion, a dragon, and a bird of prey (either a phoenix or an eagle, we aren't sure). Thanks, Kotaku.
A May 2012 announcement would likely be followed by some sort of presence at E3, the annual Los Angeles video game convention. The game would also be shown at Quakecon 2012 in August, along with id Software's Doom 4 and several other titles.
The fact that ZeniMax and Bethesda are working on an MMO is hardly a secret, as related job postings have been on ZeniMax's website for quite some time now. What remained unknown until now was the universe in which this MMO would take place.