Google SSL cert just expired (twitter.com)

Specifically it's the intermediate certificate that expired.

Can we have this title changed to 'smtp.google.com SSL cert expired'? I see no reason to keep it ambiguous.

Wouldn't it be great if there was a service that..

Oh, someone has already built it, of course:

http://certalert.me/

I don't understand. Google has their own CA and does regular certificate rotation for their web sites. How can a company like that not have every certificate change scheduled? Even small companies would have them diarised.