Just read about it at Gmail New Features page…
G is for growth
Storage is an important part of email, but that doesn’t mean you should have to worry about it. To celebrate our one-year birthday, we’re giving everyone one more gigabyte. But why stop the party there? Our plan is to continue growing your storage beyond 2GBs by giving you more space as we are able. We know that email will only become more important in people’s lives, and we want Gmail to keep up with our users and their needs. From Gmail, you can expect more.
On my account it shows 1085 MB and if it is April Fool’s joke then I would say, real Bad Joke lol