it has one gig...
when you fill it up, it won't start deleting/bouncing messages until you reach 1024mb.. they put in 1000 for some stupid reason, prolly because most people wouldn't get the idea...
so in the end you could reach up to 104% or so..
And no, email is not more professional as HTML.. I don't use HTML in my messages, I don't allow html (when I was using yahoo) and I've never seen a drop of it in any of my personal messages anyway, unless it was from FAMILY, never had a drop of html in any of my work emails...
what's html do for email anyway? Put in time/bandwidth wasting formatting where plain text would have been just fine to send