First Ashton and Demi were like, OMG Twitter! and then Larry and Ashton were like, OMG, Twitter! and then Oprah was like, OMG Twitter and then Twitter was like, OMG Oprah!.
Or, to put it another way:
There are legitimate reasons to fear sudden popularity. A site where users collaborate on a shared resource, say a Wikipedia or a Reddit (not to mention Usenet) have good reason to fear an influx of new users who “don't understand” the site, and might change its character.
Twitter's not like that, though. It's like the web itself: a loosely connected accumulation of linked communities. You only ever have to see the people you want to see. So if Oprah brings all her viewers on to Twitter, you never have to see a single one of them if you don't want to. The community that you are a part of changes not one jot.
So the only real reason to care you were #herebeforeoprah would be the same reason you liked that indie band before they were featured in an iPod advertisement.
I hate to break it to you, but Twitter was never that cool.
(On the other hand, Twitter seems to be revisiting its old habits as far as uptime goes, but pretty much every popular Internet service has experienced those kind of growing pains. They either reach a point where the growth curve flattens out and settle down, or they collapse under their own weight and are replaced by something that can handle the load.)