Ok I'm now sure that the Google Gmail service was not a 1 April joke from Google.

Why do they offer 1GB you ask? Well most users will only use a few 10MB's on short-term, and people interested to use this for warez will not be given a chance I think. Google will probably have developed a routine script or something like that which looks for 'strange behaviour' on their webservers...

The whole article can be found here