(NYT) Philip Kaplan earned notoriety and profit a decade ago with a site that chronicled the implosion of the Internet bubble. Now he is back with a project that seems sure to get attention again: Blippy a soon-to-start online social network that lets you share details of your credit card purchases with friends or strangers.

Mr. Kaplan’s earlier venture, an obscenely named Web site that parodied FastCompany magazine, chronicled the dot-com carnage in 2000 and 2001. Though that site trashed failing start-ups, Mr. Kaplan was an entrepreneur himself: he made money by devising a self-service tool that allowed advertisers to place ads on the site. The tool worked so well that in 2002, he spun it off to create AdBrite, which places ads on more than 100,000 affiliated sites and had 2008 revenue of $31.6 million.

Still chairman and a major shareholder, Mr. Kaplan, now 34. left his chief executive role at AdBrite last year, turning its management over to a hired chief executive and freeing himself to noodle. Most of his tinkering is based on the potential of social media sites like Twitter, where he goes by the name Pud. In June, he became entrepreneur in residence at the venture capital firm Charles River Ventures, but after just half a year, he left to work full time on Blippy.

Currently in invitation-only beta testing and headed for a public introduction in 2010, Blippy reports your credit card purchases (for example, “Alice spent $47.60 at Macy’s”) to others, as if the transactions were tweets on Twitter or Facebook status updates.

Mr. Kaplan spoke about Blippy earlier this week. A condensed version of the conversation follows.

Q. Before we start — on Aug. 30, you tweeted: “Getting married. About to walk down aisle. Putting phone on vibrate.” Really?

A. Yes, that was true. I was about to walk down, and at the last moment I realized my phone was still on, so I tweeted that out real quick. My wife is also a fan of technology, so she appreciated it.

Q. So how does Blippy work?

A. The idea is that most Americans have two or three credit cards in their wallet. You sign one of them up to be the social card — it’s connected to the site. The other cards you keep private. If I use my public card at a Starbucks, for instance, all my friends know that I’m at the Starbucks, and they can come and see me, or whatever.

Q. And you wouldn’t need to announce that via Twitter — it just shows up online?

A. We call it passive sharing.

Q. But even on my public card, I’d control who sees what I’m buying?

A. You can make your account public or private, like on Twitter where you can protect your stream and only people you approve will see it. And it’s only going to show the charges you want it to show. Some people are only sharing their iTunes or Amazonpurchases. The cool thing about iTunes and Amazon is that you can show the exact product that you’re buying, not just the amount.

Q. So you’re not going to sell me out when I buy a Wang Chung song online?

A. You won’t have to worry about any private information being sold.

Q. Talk about conspicuous consumption. This probably isn’t for everyone.

A. I guess you need to have the right temperament if you to want to blog and tweet and Facebook and all that. It’s just another way of saying, “Here’s what I’m doing,” or “Here’s where I am,” or “Here’s a band that I’m really into” — obviously, because I just bought five of their albums.

There are roughly 100 people using the site now, friends of ours. It’s going to be invite-only for a while. The best thing is the unintended coincidences that happen. My brother spent $4,000 at Crutchfield, an electronics store. I asked him what he bought, and he said a TV. I said: “I’m in the market for a TV. That looks a little expensive, but tell me about it.” He had done all this research — who knew? I wouldn’t have known which of my trusted friends to ask about it.

Q. Is this a Twitter app?

A. It’s not currently tied in with any other social network. It looks similar to Twitter but our data is structured. Unlike a Tweet or a Facebook status update, every “Blip” — as we’re calling them — is the same format, which is: “X spent Y dollars at Z.” You can click on the Z to see who else spent money at Z. Or you can click on the X to see what else that person is buying.

Q. So you can aggregate spending data?

A. Yeah, there’s a lot of interesting data we’re hoping to provide to users. For instance, you can see people paying different amounts for the same thing: phone bills, cable bills, haircuts, gym memberships.

Q. Won’t marketers be able to see what people are buying and aim ads at your users?

A. Not any differently than they can see what you’re Tweeting or what you’re blogging about. It’s probably more interesting to marketers, but that’s not our focus. Our focus is just in making it a really fun and interesting place for our users.

Q. You left your job at Charles River Ventures to do this. What kind of funding do you have?

A. We’re not making any funding announcements yet. But obviously we came out of C.R.V.

Q. How did Blippy get started?

A. I met the other two Blippy co-founders at C.R.V., Ashvin Kumar and Chris Estreich. They originally built the concept, and I was popping into their office every day, trading ideas. The more I worked on it, the more excited I got, to the point where I couldn’t think about anything else and basically begged to work on it together. Now I’m full-time Blippy.

Q. Is there a revenue model cooked into the plan?

A. We’re evaluating different ways to generate revenue, but right now we’re just focusing on making the best product we can.

Q. Do you ever think about starting your parody site back up? There would be plenty of material these days.

A. I guess I don’t have that negative feeling that I had back then. Back then, I saw a lot of money being wasted, a lot of ridiculous companies. But I’m kind of liking what I see now. And the failures these days are banks and car companies. It’s not so funny now.

Q. But people lost jobs at pets.com and you had fun with that.

A. Well, it’s never funny when people lose jobs, and that was kind of the whole point of [the parody site]. It was kind of the voice of the worker. But I don’t see mistakes like that anymore, companies like furniture.com where they would spend more to ship the furniture than they would make on the furniture — so the more they sold, the faster they would go out of business. I think people have learned their lessons. The companies that don’t have revenue streams today, it’s by choice.

Q. How is Blippy different from the kind of company that your site would have destroyed?

A. [That site] covered companies that were spending millions and doing big layoffs. A recurring theme is, “This company could be run by just three programmers and a pot of coffee.” Which is exactly what we’re doing. [That site] would be proud.