Originally posted by kestra
It matters to A LOT of people on both sides (people who are pro or against gay rights). As Ari said, it would be a first; just like the first female prez, first gay prez, first Muslim prez, etc...
But there's a difference between statistical curiosity ("Hey look, this is the first president who's never been a state governor before") and things that are of major personal interest, like the three you mention above.

Ask a black person who was alive during MLK's time and you'll understand why it's so important. Many gay people today are still harassed, beaten and killed SOLELY because of their sexuality. Having a gay president of the United States would send an unequivocal message to the country and the rest of the world, saying WE ARE EQUAL.
...steps down from his soapbox
The fact is, though, that that equality simply doesn't exist. The more people talk about it, the more obviously it doesn't exist. By the way, can I please put a [citation needed] tag on most of your statements?