It's plastered literally all over the American news sites that I visit, so I suppose it's simply a matter of what the outlets choose to cover (as with everything, of course).
The vote isn't until Thursday the 18th, and should the referendum receive a "yes," well, nothing much will happen right away as it stands. It would take quite a bit of time to work out the fine details of a movement for independence, and should that happen, I believe the proposed "Independence Day" would be in March 2016. In the event of a "no," there would still be some not-insignificant changes to Scotland's authority.
also provides a very basic overview for those not already familiar with the topic.
I have no pony in this race, so I'll be stepping away now, but there's some more information in a quick summary if it helps.