, a four-month-old startup funded partially by Twitter co-founder Evan Williams, lets you create a "social stream" of all your credit card purchases. You set up an account, punch in your credit card number, and then Blippy automatically posts all of your purchases (including their prices) to your profile.

It's basically a massive privacy invasion, only it's voluntary -- and, for whatever reason, people like it. Today, however, a few of Blippy's users realized the service was inadvertently sharing far more than they realized.

Someone discovered that by performing a targeted Google search, you could find a small handful of users' credit card numbers hidden within their Blippy profile pages. The glitch was initially publicized in a report posted Friday at tech blog .

The credit card numbers were apparently stored inside the HTML code of the Blippy.com pages. They wouldn't show up when viewing the pages in a normal browser, but they were present and therefore accessible to the eyes of a search engine.