Fleck lets users add notes to Web pages, viewable by other Fleck users. Unlike other Web-annotation services, it doesn't require you to download and install anything on your PC or in your browser.

TechCrunch writes:

This is a relatively crowded space, the two services I'm most familiar with for collaborative annotation are TrailFire and Diigo. Stickis is just around the corner too. Fleck's primary point of differentiation so far is that anyone can use it without creating an account or installing a browser plug-in. That could make all the difference. Other annotation services generally have a higher barrier to adoption by casual users. The primary barrier to using Fleck is that it only supports Firefox - hopefully that will change soon, because accessibility is what the service really has to offer so far.

This is a different approach, similar goal, to AboutUs, which we blogged about Wednesday.. AboutUs is a wiki containing information about Web sites. It's seeded by whois entries and other public documents, but the goal is that users will write what they know about sites on the Web.

As with AboutUs, the problem Fleck faces is the Web 2.0 Catch-22: It won't be useful until lots of people use it, and people won't use it until it's useful.

I can foresee a situation where people curious for more information about a particular Web page turn to Fleck, enter in the URL, and call up the annotations. Then, if they want to add their $0.02, they'll add their own annotations. But none of that will happen unless users who are just trying out the service see useful information there.

Wikipedia works because millions of people go to the site and find useful articles like this one.. That encourages users to become regulars at Wikipedia, which encourages some to eventually participate in writing articles. If every article on Wikipedia was a dry capsule like this containing information available easily elsewhere, then Wikipedia would never have taken off.

I wanted to include a link here to an InformationWeek article marked up with Fleck, so you could see how it looks. I successfully annotated a page, then clicked the "blog" button on the Fleck toolbar. Fleck generated a URL for me to post elsewhere--but when I checked the URL, it didn't work. Clicking the "save" button before clicking "blog" didn't make any difference, Hopefully, this is just a bug in the system, and will be fixed quickly--because bugs like that are the biggest obstacle to a site like Fleck achieving critical mass; nothing will alienate users faster than having their work disappear into the bit bucket.

TechCrunch had better luck than I; to get a gander at Fleck, check out this marked-up TechCrunch page.