Twitter is over capacity ?

Just now when we tried to login our Twitter account, we got the following error interface:

“Twitter is over capacity.

Please wait a moment and try again. Fro more information, check out Twitter Status.”

This is so weird!  We never thought a big site like Twitter can be over capacity ? Or it is really there are too many Twitter visitors in this world ? Is it a good thing or bad thing for Twitter ?

we can follow Twitter Status page to get more detail information.