As an interesting note, this was followed up in the DS9 novels... mind you, I haven't read all the ones dealing with it, so can't tell you how it ended up. I think every fanfic author has written a continuation at some point... I know I did in the late 90s.
How does that make sense, since they had already introduced the Borg episodes before with Q bringing them over?
You know, now that we have this movie, any future TV show will reflect the changes to this new history, as long as it takes place after the movie. Hell, they could do TNG era Enterprise and it may not even have Picard or Riker, depending on how much things change based on Nero coming to the past. One thing to remember about this kind of time travel is that it's effects are exponential in relationship to the amount of time that passes. So while relatively little may change in 20 year, 100 years later could be completely different from the original time line.
Q didn't bring the Borg over, nor was the episode Q who? the first time the Borg encountered the Federation. At the end of Season 1 of TNG the Romulans are brought out from behind the Neutral Zone because Federation and Romulan outposts are destroyed... scooped out of their planets. Its accepted that this is actually the first time the Borg ventured into the Alpha Quadrant and that the Enterprise encounter wasn't the first.
