I keep thinking about Lucas's comment that Pinterest is NOT building a general interest site.

Thank goodness, since the word I most often hear Pinterest's users employ to describe the application is addictive. General interest would be too addictive.

I was trying to figure out why some people find Pinterest to be addictive.

The BusinessWeek article claims that people find browsing and discovery to be addictive:

Since the site is image-centric, it’s an attractive way to browse. “Once you know what you want, Google or Amazon will take care of it,” says Ben Silbermann, a founder. “But if you don’t know what you want and you want to discover, I don’t think there are very good solutions.”

I take this to mean two things:

• Pinterest is simple to learn and easy to use.

• Using Pinterest feels like shopping without paying. It is the browsing-at-the-mall experience so many of us know and love.

Browsing at the mall can be addictive.

And now, browsing online can be addictive too: not just stuff from Amazon and Etsy but plenty of Tumblr goodies and everywhere else on the Web, too.

So I think Lucas is right: Pinterest not general purpose.

But I do believe it's very addictive for the person who wants to browse casually.

I didn't realize that Time magazine called Pinterest, Google-Plus, and Klout the best social media sites of 2011.

But that article does point to another reason why Pinterest is addictive to some:

The soft-spoken 29-year-old believes Pinterest fills a need on the Internet for people to express themselves. You don't have to be witty, or a good photographer, or a good writer to use Pinterest, he says, you just have to pin your interests to an online pinboard.

If you can press a button, you can express yourself on the Internet. It makes Tumblr seem like calculus; to Pinterest something, you don't even have to know what blogging or tweeting are.

Maybe there's something profound to that.

But it's notable that Pinterest was not a hit at first:

The founders spent two and a half months on the basic screen of Pinterest. They figured it was the most important part of the website. It needed to be inviting. The rest of the site would depend on it. They built 50 fully coded versions of the screen, and toiled over it until they found what they thought was the perfect one.

They launched the site in March 2010. It was greeted with silence. " It was like stealth without us trying to be stealth," he said.

There were ups and downs in the early days. Stuff broke and nobody cared because nobody was using the site. There were productive days and unproductive days.

"It wasn't interesting, it was just kind of sad," Silbermann said, smiling.

Somewhere between there and here, Pinterest got addictive.

Plus now they've given me a tool to embed pictures Flickr-style: