Google made two announcements: The GMail Paper and the Google TiSP
Now for those who still haven't realized, both of these are Google gags that they typically play on April 1st. Go to http://www.google.com/tisp/notfound.html to see links to other gags they've played in the past as well.
The GMail Paper thingy was funny. I had actually worked on a similar service provided by Alacrity Homes when they were new to the Internet. We had built up their site way back in 1999 and a traditional construction company in Kerala going on the Internet was a very new thing back then. Some smart people at Alacrity realized the value of using the Internet as a medium for NRIs to be able to view properties (in full 3D) and then choose to book them online. Now to popularize their new website (which by the way no longer exists), they also provided a free service that allowed people to submit a mail form, which Alacrity would print on a postcard and send to whosoever you wanted to. The connection of email to snail mail.
The service was a real innovative idea. Interestingly enough, the Indian Postal Department is still offering a similar service: http://www.indiapost.gov.in/IndiaPost-E-Post.html
So when GMail Paper did sound absurd, the foundation of the idea does exist. Only, I don't personally believe there will be huge value in the same, thanks to Internet penetration reaching almost every nook and corner. Also, with telephone being far more cheaper a medium than it was once, I don't think snail mail forms the primary means of communication in most places. There might still be the odd official form that required your signature to be sent - and that would not quite anyway work through the e-medium.
In other April Fools gags, there was the Microsoft Penguin Adoption Story (which by the way was not originated by Microsoft) and people speculating if the big announcement by Apple and EMI to provide DRM-free music on the iTunes was also an April Fools story.
Lessons to corporates: Don't make your killer (real) announcements on April 1st.
Lessons to us: Don't believe any announcements that do get made.
I wonder if some day a prank like this will cost somebody tons of money in a false stock market boom and eventually get the company sued. Hmm...