The state of the Web 2.0 economy is an evergreen topic in the blogosphere. Pundits like to check under the hood to examine if this era is anything like the Web 1.0 bubble.

So far, indications are that the excitement around Web 2.0 is different from last time. Entrepreneurs aren't minting paper millions on Wall Street -- the companies being sold are real businesses with real revenue.

Dig deeper, however, and there are troubling signs of overindulgence.

In-boxes, smart phones and IM windows are overflowing. Always-on connections, mobile devices and new publishing tools have expanded the media we consume to include content from peers. Further, new networks and platforms for participation are sprouting up and going supernova overnight, with no end in sight.

Photo: JC Bourcart

Steve Rubel is a marketing strategist and blogger. He is senior VP in Edelman's Me2Revolution practice.

The problem is that human attention, unlike technology, has limits. There are only so many digital inputs we can realistically pay quality attention to in our busy, multitasked lives. Demands for our attention have outstripped our finite supply of time. A crash is coming, folks. But this time it's not financial -- it's personal.

Consider popular blogger Robert Scoble. He used to spend three hours a day reading 1,000 RSS feeds and sharing the best bits. However, even he is cutting back: He has reduced his feed diet and now mostly answers e-mail when he's on planes and away from the web.

There are plenty more like him. Delta's Sky magazine this month spotlights America's growing CrackBerry crisis. Surely Dr. Phil will take up the topic soon. This is prompting some, such as tech blogger Mark Evans, to make radical changes. "The CrackBerry was making me crazy. It controlled me as opposed to the other way around," he wrote on his blog.

The attention crisis is an epidemic. There's no more room at the inn. People will cut back. The key question is: What will they trim? Ad-supported media, or content from peers?

Some will crave the media's ability to edit; others will want to stay closer to their friends. What's unmistakable is that choices will be made. And while there seems to be no end in sight for the growth of social media, if this happens en masse, will ad revenue sag, causing a financial pullback? Possibly. There's no black-and-white answer here.