WebMynd, a startup launched in January, has come out with a browser extension that keeps a record of every Web page you view. It's a nifty tool, but a word of warning to would-be users: You may want to shut it off sometimes.

WebMynd's app is a free, downloadable add-on for Firefox 2 and Firefox 3. WebMynd takes a snapshot of every Web page you visit and stores a copy of the page on your PC hard drive. The text from all pages is stored on WebMynd servers, where they're indexed to facilitate searching.

It's a nifty application for anyone who might need to go back and find a Web page they once visited. In that respect, it's kind of like a bookmarked page or a browser's drop-down menu of recently visited Web pages, but WebMynd's different in several respects. For one thing, it presents a mini replica of the pages you visited in chronological order, so navigating your Web history is visual and intuitive. You can see what that looks like here.

Also, WebMynd lets you do word searches on your Web page history. So, if you're looking a medical term or product name, you can get back to that page easily.

The obvious question: Is it a good idea to keep a record of every page you visit? WebMynd's sample history, for example, includes a few pages from the Victoria's Secret site. You may want to disable the recording mechanism when shopping for underwear, especially from the office. WebMynd can be turned off with a click of the mouse.

For privacy and security, WebMynd doesn't require user registration, nor does it store passwords and user names that might be entered when you're visiting a Web page.

WebMynd is funded by venture firm Y Combinator. In the months ahead, WebMynd will add support for the Internet Explorer and Safari browsers. Planned features include tagging options for pages, bundling sites together, and a collective "mynd" where multiple users can store and share pages.

I met WebMynd co-founder CEO Patrick Buckley recently, and he described how the browser add-on works. Here's the interview.