Yahoo community manager Matt Warburton sent out the following message to members of the company's experimental social network Yahoo Mash: "Thank you for trying out our Mash Beta service. We hope you had fun with it. Please note that we will shut down Mash on September 29, 2008. As a result, your current profile on Mash will no longer be available." It's an embarrassing end for Yahoo Mash, which only launched last October. But it's not as embarrassing as its beginning, when Yahoo felt it had to promote the site via Facebook message.