We got it easy in Trek land, canon is simple with only a couple grey areas thanks to Roddenberry's apocrypha pronouncements. In SW there are canon layers.
George Lucas himself considers only the Star Wars movies and the Clone Wars cartoons to be canon. The Star Wars EU canon appears to be a marketing ploy, and in reality no more binding on the tv/movie SW canon than in Trek.
George Lucas wrote:
I don't read that stuff. I haven't read any of the novels. I don't know anything about that world. That's a different world than my world. But I do try to keep it consistent. The way I do it now is they have a Star Wars Encyclopedia. So if I come up with a name or something else, I look it up and see if it has already been used. When I said [other people] could make their own Star Wars stories, we decided that, like Star Trek, we would have two universes: My universe and then this other one. They try to make their universe as consistent with mine as possible, but obviously they get enthusiastic and want to go off in other directions.
The fans have made it considerably more complicated than that:
G-canon: The latest versions of the six movies
T-canon: The CGI Clone Wars movie and TV series and the unproduced live-action TV series
C-canon: most of the modern (i.e. 1991 onwards) EU
S-canon: older EU that may be ignored by current authors
N-canon: non-canon, including deliberately hypothetical stories, etc.
Now that Treklit is cohesive there is the expectation that it will be a canon within itself. If someone writes a novel in which Janeway is alive set post B.D. with no reference to how this came to be it will cause a Treklit canon problem. Fans won't expect the novels to be taken into account if there is another tv show though, unlike the Clone Wars debates.
A quote from a SW friend of mine:
"The biggest problem is that fans get invested in details in the EU which are part of C-canon (but not T- or G-canon) and so technically are part of the SW continuity, at least from an EU POV. When T-canon alters a bit of EU continuity (such as the nature of the planet Ryloth) suddenly a fact in C-canon that has existed since the late '80s (IIRC) gets retconned away, causing much distress.
The truth is that C-canon is pretty unstable ATM, given that over seven hours of new superior-canon material is being produced per year, which is about 10 times more than when the prequels were in full swing. The EU voluntarily gives The Clone Wars unilateral power to alter EU continuity as it sees fit, but EU fans place the onus on Lucas and Filoni to refrain from using that power--it's totally backwards. In any case, the EU continuity is now in the position of being totally untrustworthy even in respect to itself, since anything could be rewritten from above at any moment, shattering the illusion of a cohesive universe."
Lucas also drew a direct parallel to Roddenberry's simple solution of if it's on screen it's canon and if it's in a book it's not canon, see this Lucas quote:
""There's three pillars: the father, the son and the holy ghost. I'm the father, Howard Roffman [president of Lucas Licensing] is the son and the holy ghost is the fans, this kind of ethereal world of people coming up with all kinds of different ideas and histories. Now these three different pillars don't always match, but the movies and TV shows are all under my control and they are consistent within themselves. Howard tries to be consistent but sometimes he goes off on tangents and it's hard to hold him back. He once said to me that there are two Star Trek universes: there's the TV show and then there's all the spin-offs. He said that these were completely different and didn't have anything to do with each other. So I said, 'OK, go ahead.'""
But it seems fans have a deeply vested interest in EU.
JJ really set himself free of it ever ending up like that in Trekland in bypassing the timeline of both onscreen and in books, LOL.
Anyway sorry for this SW interruption, hope someone found it interesting.