Hi I know that TESO is set back in the past compared to TES , but What are the main differences?

What will happen to TES lore if TESO scripters will invent new events and stuff for their game?

Will Bethesda consider that new lore or instead go for their own route and skip all new additions and keep going for their original views?

My fear is that a MMORPG like TESO might be ruining the TES lore by spoiling too much stuff, inventing new things that are ok for a multiplayer but make few sense for a single player and that it might stress too much the lore in terms of events, historical happenings and figures that the TES will suffer from it .

TESO did invent several rather outlandish things, but it's important to remember that it happens in the late Second Era. In Skyrim, we're already in the Fourth Era, some 600 years later. TES did this kind of thing before, with the Greg Keyes novels: the events in these books have been alluded to in Skyrim, but not in any overt way, and you don't miss anything by not reading the books.

I honestly doubt Beth will allow Zenimax Online too much wiggle room in regards to new ideas. We won't see anything like exploring Akavir, anything kept mostly in the dark, until Bethesda wants us too.

The only real "contributions" (if you can call them that) I expect are anachronisms and "transcription errors" that serve to make the world more and more generic.

Of course I likely won't pay much attention. When I found out they were putting in The Lusty Argonian Maid CENTURIES before its author was even born, I pretty much lost all faith in Zenimax and the Colonel as far as lore and writing are concerned.

My biggest worry for ESO is that the provinces won't be given the proper treatment a single-player game would offer. Not because Zenimax is bad or anything, but they can't devote all their time to one province and the cultures that resides within, then Bethesda may be bound by the things that Zenimax does come up with.

Honestly, most of the things I've seen in the beta so far are perfectly fine and interesting in terms of lore. I wouldn't debate whether the game is non-canon or not until it actually comes out.

Expect more generic cultural blending like this:

http://www.gamesas.com/topic/1483625-pelinal-whitestrake/?p=23251319

And from Skyrim, we can see this really isn't something restricted to TESO. This seems to be the direction TES is going.