I could have sworn that a discussion here years ago about canon revealed that on startrek.com they actually define canon as being any onscreen (TV and movie) Trek and non canon is all other forms.
Which makes sense. Perfect sense, but for example today the books are trying very hard to stay consistent with each other. So really right now we have four different universes for Star Trek. Well, maybe five but someone can correct me on the fifth. And this is my opinion of course. Not a fact.
Old Universe (or Original Universe):
This is Trek on TV and all the movies before the reboot. All Trek universes try to stay consistent to this universe when it can.
New Universe (or NuTrek):
This is the reboot universe that creates an alternate universe using time travel. Everything in the Old Universe had to happen to cause this one. I bet to many fans disappointment (not mine, but just saying), ENT occurs in both universes.
Books (or BookVerse or BetaVerse):
This is the current book continuity. The books that expand the original universe threw books. With no new content of the Old Universe this could be considered the continuation of that universe.
Star Trek Online (or Star Trek Online.... I guess):
Star Trek Online uses all three universes to create this forth one. For those who don't know, it takes place in the 25th century after Nero travels to the past. The Federation and Klingons are at war, and they are about to add the Romulan Republic as a third playable faction. The Republic is the remains of the Romulan people after the destruction of Romulas as shown in NuTrek. At the same time, some aspects of the BookVerse has been incorporated into Star Trek Online, but none of the universe changing events of the past couple years.
Shatner's books (or the Shantnerverse):
I've heard this term before to reference William Shatner's Star Trek books. I've read a few, and other then the fact Kirk is alive in the 24th century, the book universe almost entirely ignores these books.
Just my opinion of course and I'm not telling all of you to accept it. Its just something I've thought about recently talking to a friend who is a huge Star Wars fan explaining to me the convoluted mess that is Star Wars canon.