The site was announced at www.wrafter.com on April 10th (no link avaliable, no cache avaliable except for the Google.blog heading info), and the domain name was registered on the second of June. A friend pointed out that April 11th was the day the Cloudmakers started up - a somewhat tenuous supportment of the this-is-a-web-game hypothesis. Additionally, the following text is contained in the html of the PostExpression website, because of course people think that there is a game involved! The banner postexpression.com hosts is so darn obfuscate of purpose: "Looking Here Won't Give You (M)Any Clues, But Nice Try"
Who is this, Al Gore?
There is an option to register to be in a "second wave" of membership. Those one hundred in the first wave recieve an altered banner image (but not a hosted image, all instances of the image I have found have been imageshacked, not deeplinked) that denotes their status.
To learn the rules of the "game", you need to sign up at the site, and then click the HERE button on the page following data input, this takes you to the rules page.
Offhand, this looks like little more then a device to spread the word about a new community. A bit of looking around the Internet reveals that people like the banner, but have no idea what the Hell postexpression.com actually is.
Updated 6/19. At Mark Wrafter's website. Highlight the image to get a message. Go to the image directory to find a txt message here. This has the same message as the one hidden in the
Brief google search turns up Commsforspirits.com. There is a
Phase 2 here.