Google Gmail gives you more than 2.7 GB of Inbox space sufficient to store hundreds of thousands of email messages. But you can quickly run out of space even on GMail if your friends regularly email you PDF, video attachments, sound clips, large zipped files, or high-resolution photographs. Over at Digital Inspiration there is a post about Keeping your GMail Inbox size under control.
There was alot of stuff in there I hadn’t run across before.
If you are using Gmail as a memory dump, you probably should have a look.