If you've participated in online forums, you've probably had the NSFW (Not Safe For Work) experience: Someone posts a link to something NSFW without adding appropriate warnings or disclaimers - either as a blatant troll, or without considering varied tastes and situations (e.g. someone sitting in their underwear at home posts a link to a questionable "funny" video that others are blindly opening in their workplace). Often the URL is obscured and indecipherable courtesy of "helpful" services like http://tinyurl.com/

Web 2.0 to the rescue!

Through the magic of collaboration and the power of many eyes making all troll/porn/questionable sites shallow, I propose an innovative new web service that allows users to add URLs, or whole domains, indicating the degrees and types of questionable content, perhaps using the power of folksonomy to tag the URLs. They can add descriptions using a Wiki-style interface, all powered by an AJAX-rich DHTML web application. Think http://del.icio.us/ + http://www.flickr.com + http://www.wikipedia.com + http://www.netnanny.com/.

Via an exposed open-API XML web service, an extension for Firefox can be created that would allow work users to browse more safely, as it automatically validates all URLs through the NSFW service, blocking or warning on potentially questionable content. For those who worry about the privacy ramifications of having all URLs auto-validated, they could manually validate select URLs, or perhaps download the latest "Current Widely Seen NSFW Websites" filter list and use that in their browser extension.

Sounds good, doesn't it? Any VCs out there ready to send me some start-up capital? I'm thinking in the 7-figures range.

Of course in actuality I think it would be a disaster. Not only is it the sort of service that most people wouldn't pay a penny for (yet without a large userbase you can't have useable community-driven rankings, and of course you can't have a professional taxonomy classification of the sites without revenue, as that costs real money), there are limited ancillary revenue options (it'd just be a tiny service that people use almost unconsciously - there is no stickiness). Until it gets a large userbase - which it is doubtful that it ever would as a user-contributed service -  it would suffer from significant false-negatives through exclusion as well, not to mention that it could be easily gamed to cause false-positives.

A classic chicken-egg problem.

On top of that, varying scales of puritanism, as well as trolling with the site itself, would lead to extraordinary pollution of the database. You could try some sort of web-of-trust with relationships and personal networks, for instance only trusting rankings coming from those you trust (or who people you trust trust, and so on) but again that would vastly limit the scope of applicable NSFW rankings, rendering it close to useless for all but the most common of links.

[I should also note that people were tossing around ideas for collaborative, community-driven rankings of websites over a decade ago. The idea of community-driven content is hardly new. What is new is that people think they can build a revenue model on it, largely on the back of Google's innovative and prolific Adsense]