As far as I know there are usually several categorisations of canon for any particular brand. what are the categories for Star Trek and how does the Star Trek Online game fit into those categories?
Note that the Star Trek online game is not only licenced but apparently everything in it has to be approved by CBS before being used.
There is no "standard" canon defined by a central authority for Star Trek, like the way the Lucas Empire Disney Empire defines one for Star Wars.
Having said that, there's a "commonly accepted" situation described in detail on Memory Alpha Canon page:
The Star Trek canon is generally defined as all live-action television series and feature films released by Paramount Pictures. With the release of Star Trek: The Animated Series on DVD, the studio appears to have changed its stance, and is now listing the cartoon series (aired 1973–1974), as a part of established canon.
A large body of licensed Star Trek works exists that, while approved for publication by Paramount, are not considered part of Star Trek canon. This includes novels, comics, games, and older reference books such as the Star Fleet Technical Manual.
As such, STO MMO as a game is NOT "canon", under the best definition of "canon" that Star Trek has.
It's likely to assume that one of the big reasons canonicity is such a problem is because of the way Star Trek is handled through licensing.
CBS owns the rights to shows, and Paramount to the movies. CBS was able to get a hold of the rights to the show when it was owned by the old Viacom, which also owned Paramount.
When Viacom split from CBS, and CBS became its own powerful entity, it took the rights to the shows. Paramount, along with Viacom, still owned the rights to the movies. Unfortunately, this created such a problem for the company (tried to find the name but can't find it) who was first licensed to bring forth a Star Trek MMO.
They talked about the difficulties keeping within canon, due to the politics behind the scenes. For instance, in order to get rights to model the Sovereign class, they needed approval from Paramount (as they owned the rights to the first piece of film that style ship was even seen in), for the Galaxy, they had to turn to CBS. The problem became even more complicated when it came to the Constitution class, as although the original was on TV (CBS), the refit was in Star Trek: The Motion Picture (Paramount), and there became a brief argument over who the rights for the ship belonged to, due to the fact that although they looked different, they were in fact still classified as the same ship.
Thankfully, the company who originally tried to make the MMO sold the rights to Cryptic, and the groundwork for issues such as these had already been laid. Cryptic also noted early on that the process was slow and arduous just to get rights for other ships and characters.
It's also likely to assume another big problem stems from the conflicts within the ownership of rights system. It's no secret the shows are canon, but with the inconsistencies the shows contain (such as the Hansens looking for the Borg with knowledge of them 10 years before the ENT-D encounters them), the problem, in theory could become "what are we willing to acknowledge and ignore?", and this would just be on the CBS side. Paramount's side would make the Borg as character/race even more complicated. We all know the Borg originated on The Next Generation, but First Contact was the first time we saw a Sphere, so the rights to the Borg as a race could be from CBS but the ships were split between the two. Also we see numerous Borg ships in red alerts that look exactly like V'ger's ship from The Motion Picture, and the Shatnerverse tells the story of how V'ger was, at least in part, a precursor of the Borg, and the rights for the design of that ship would come from Paramount. So with everything for just the Borg, in terms of STO, this could possibly mean that the origin of the Borg has already been explained through TMP to a certain degree, and further explained through the Shatnerverse, but since the Shatnerverse, according to Starterk.com/faq, is not considered canon.
In the sense of the game, the canonicity of the Borg's history could be ruled as canon specifically for the game and not the movies or shows, but could also very well be considered apocrypha and never fully explained, due to the various source material they chose from.
And, finally with every answer, there may be even more questions both CBS and Paramount are unable to answer or don't care to answer. If V'ger's ship is being used by the Borg, and the origination story from the Shatnerverse is being used, wouldn't that make, at least in part the Shatnerverse canon? Questions such as these would open up many other questions that have already been answered by the FaQ, but citing specifics would make those statements contradictory to what has already happened.
I think in the formal sense, STO cannot easily be classified as one or the other as far as canon is concerned. As with everything else Trek, though, it's hard to answer these questions, but in this specific, it may just be as simple as "maybe", since no one with the rights to the IP's wish to comment otherwise.
When STO was originally advertised and discussed CBS and the developers of STO said that it was the canon continuation of Star Trek in the Prime Timeline. At that time there were no plans for future series (as there still aren't, only a prequel series). These rules that CBS had for canon were the same back then, and it was considered exempted and above the status of other games. However, because it is largely out of the control of CBS and CBS not caring to maintain what they've said with properties outside of the live action TV series CBS probably will not take it as canon going forward.
So it is "canon" but no one will treat it as such, making it effectively not canon. It's the same with TAS. It is canon, but most people don't take it as such so it largely isn't. You can see this with a number of episodes too. The episode where Voyager's crew achieves Warp 10 is canon, but it was ignored by writers and most fans refuse to take it as such. So it effectively kicks it out of canon even if it is "technically" in canon.
