the story: The ship gives birth to an artificial intelligence, and the crew experiences this via a holodeck ride on the Orient Express.
what it's all about: The last word in a longstanding thread woven throughout the series, not the least in the form of Data himself, "Emergence" is otherwise a minor and somewhat baffling addition to it, that just seems to have been done because it was a cool idea.
Remember "Evolution" from the third season? "Emergence" is kind of the throwaway version of it. You can choose to think of it as a holodeck episode, because that aspect of the story is the most memorable, even if it also typifies the randomness of holodeck episodes, or at least their reputation. But it's better to think, if you want to give a somewhat entertaining episode its due, the strongest link to significance possible. So that leaves us with a ship trying desperately to communicate with its crew.
By the time the Enterprise-D gives birth at the end of the episode, you'll naturally wonder if we ever hear about this again, if the ship suffers from post-partum depression, etc., and of course this is a one-off episode, because the series is nearly done, and if anything the entirety of "Emergence" can be seen as a metaphor, a thank-you to fans who helped the series endure and prosper, and the impending next spin-off, Voyager, as well as Deep Space Nine, the movies that would follow (including the death of baby's mommy!), etc.
Or don't think too much into it, accept it for what it is, a very minor achievement in Next Generation storytelling, and move on.
franchise- Move along!
- series - Good for a look at one of this show's obsessions.
character- Not important to any one character. essential- Not essential!