To be honest with you....your question is a good one. And since I am not the editor or the founder of the site I cannot say with 100% certainty that this is correct but my answer would be: yes. The main focus of the site is to cover startups. As far as I know there are no rules for only covering them when they are small. So if something I write about explodes like a Facebook or Twitter I will certainly being following up with them. In my mind that would be a "gold mine" of an article in terms of information both for myself and for our readers. Now would I beat it to death and write twelve articles about it in a five day period just to get the page views? No. That crap drives me crazy. I would like to think that I would only cover them if something significant was happening with them.
How does MacRumors decide when they are going to do another story on something that is hot?
I will check with my boss/editor and see what his thoughts are on the subject...