One of the most interesting articles I saw on the TV Tropes website is one about what they call "The Celebrity Paradox".
For those who don't know, let me explain: I think we automatically assume that when an actor plays a role in a TV show or movie, the actor themselves do not exist in that show's universe. (i.e. in the "Die Hard" movies, there's no actor named Bruce Willis). There are of course exceptions, like that awful gag in "Ocean's Twelve" where Julia Roberts' character passes herself off as Julia Roberts, but those are pretty rare, I think.
The question is how other productions and people referenced on the show (to which said actor is connected) are affected.
Some of them are far reaching. Again, TV Tropes gives a good example, from Star Trek itself: Jeri Ryan divorced her husband Jack in the 1990's. In 2004, Jack ran as the Republican nominee for US Senator from Illinois against a little-known Democratic state senator named Barack Obama. When some of the ugly details from his divorce were made public during the campaign, Jack withdrew from the race, prompting the GOP to choose a last-minute replacement (and a rather unfortunate one, at that) and Obama won handily.
Now, without that high-profile office, it's unlikely he would've had the recognition to run for president and win in 2008. Yet, if someone in the 24th Century on Voyager
were to access historical records on America's 44th president, how much of this would be present?
Another example is Rain Robinson talking about the show "Mission: Impossible". If someone were to watch some of the later episodes of the show, would they notice one of the main characters resembles a certain Vulcan Ambassador?
I'm wondering how many of these exist in Star Trek, hmmm?