1 I recognize two of the names, because Timothy Zahn created them; I never had much use for most of the other Expanded Universe novels, except when I was desperate for a read and they were the only things in the grocery store at 3am.

-j

2 Disney uncanonicalized the Expanded Universe, so technically you don't need to know who they all are.   However:  Mara Jade was the Emperor's Hand, an assassin, who married Luke.  The Yuuzhan Vong were a race that invaded the galaxy 30 years after the end of Return of the Jedi in a 17-book series that massively changed the universe.  They were responsible for the deaths of Chewbacca and two of Han and Leia's children.  Not sure about the others.

3 I don't even know what "Expanded Universe" is.

4 Everything published outside the six original movies, including cartoons.  Mainly the books.  And I didn't recognize anything after Mara Jade.

5 The expanded universe was the collection of book, video games, and comic books in the "Star Wars" universe that had some form of official recognition from LucasArts.  The most widely known are probably the first four books by Timothy Zahn, which are where we got Mara Jade and Admiral Thrawn, but the total number of books in the EU number in the hundreds by nearly that many authors.  They were officially cast aside as no long canon when Episode VII was announced, but it was worded in such a way that many people speculated that some of the characters and events, such as Admiral Thrawn, would make their way over to canon, and now he has.
Of course, the real fun is the stuff that never qualified for Expanded Universe status.  For example Splinter of the Mind's Eye, a book written before Episode V and VI came out, which had to be rather rapidly and quietly forgotten once we learned that Luke and Leia were siblings..

6 Congratulations, I think, on becoming a QoTD on Ace's blog tonight.

7 Maetenloch never comments here but he's a regular reader and has linked to me before a few times.

8 Technically there always was an expanded universe, just because Star Wars essentially pioneered the modern marketable franchise and had action figures for characters that didn't even have speaking lines in any of the movies.  The best of these, though, are the Timothy Zahn "Heir to the Empire" trilogy, that formed a very well-written story arc, that starts out just after the original trilogy left off, and deals head-on with more issues of "what happens when the rebellion succeeds?" than progressive minds are even capable of comprehending. Despite one annoying Mary Sue (the Mara Jade referenced in the Penny Arcade strip, who I guess can't be all bad because she's by far the most popular character Zahn wrote), all the original cast got their turn to shine, and none were ever strapped to an idiot ball just so Mara Sue could save them (which probably explains her popularity). Generally when people refer to The Expanded Universe, they're either referring to the Zahn books, or something based on them in the usual fanwanky way.

9 The earliest Star Wars "canon" expanded universe was probably the role-playing game.  West End created a lot of the things that are "facts" now, like the make and model of the Millennium Falcon, the manufacturers of R2-D2 and C-3PO and most of the other technology, and the first attempt to classify and sort force powers.

10 The cartoons by Disney are considered canon, which is why they were excited about Thrawn appearing in Rebels.

11 Honestly, although I read and enjoyed the entire Thrawn trilogy, I figured there was no way the series could go anywhere but downhill from there, so I never read any of the inevitable pile of sequels written after that.
Hearing some of the stuff that came later has made me quite happy with that decision. Mara Sue marries Luke Skywalker? Great, he probably got Force Cancer and died tragically young just months after, leaving only his unborn child Mara Enony Raven Way to carry his legacy.

12 Amusing urban legend that is *probably* true:

When the line of Star Wars tie in novels was started, the line writers asked for a setting bible to work from.  Lucas didn't supply one; instead, they were sent copies of the West End Games RPG, and told to use that.

13

Amusing urban legend that is *probably* true:

I doubt this story is true since, many moons ago, I read an interview that was done with Timothy Zahn and he mentioned that when he was finally selected to write for Star Wars (Which required his agent, not Zahn, to submit his previous works to Lucasfilm Licensing.), he received a large story bible for his work, besides consultation with LFL.  That seemed have been followed through-out the novel line, though LFL was very flexible about the writers they were willing to accept as long as they will willing to follow guidelines.

The story of West End Games and the Star Wars RPG (Especially the end, which could be witnessed by the world in almost real time, thanks to the Internet.), would be interesting by itself.  Something that was nice was the set of sourcebooks which covered the Thrawn Trilogy, complete with pictures of scenes from the books.

14 I actually give more credit to the WEG story; mainly because all reports of any kind of source bible or even rough outlines contributed by Lucas or Lucasfilm have always been proven to be apocryphal.  People have been searching for this compendious resources for decades now, and they keep ending up with a handful of notes scribbled on notebook paper.  I *do* remember Zahn mentioning that he was directed to the Daley and Smith novels as examples of works Lucas had found acceptable.  One gets the feeling that George Lucas wasn't actually all that involved in the process.