If I had 20gb of mailbox space, it would be highly unlikely for me to have gone over.

Have to give credit to this excellent phishing email. None of the grammar is incorrect, though it still doesn't have the right flow... and yeah, English may be a germanic language, but we don't Capitalize Every Other Word Here.

From: system.admin [mailto:info@web.com]
Sent: Friday, July 10, 2009 11:41 AM
Subject: Your Webmail Quota Has Exceeded The Set Quota/Limit

Your Webmail Quota Has Exceeded The Set Quota/Limit Which Is 20GB.
You Are Currently Running On 23GB Due To Hidden Files And Folder On Your Mailbox.
Please Click the Link Below To Validate Your Mailbox And Increase Your Quota.

www.jotform.com/form/91902921397
Failure To Click This Link And Validate Your Quota May Result In Loss Of
Important Information In Your Mailbox/Or Cause Limited Access To It.