I created a little page awhile ago that allows you to retrieve your Flickr userid number or groupid number. It actually gets used — mostly for WordPress plugins, but you can also use it for other things like embedding Flash slideshows in your site. I’ve moved the page to idGettr.com and created a Flickeresque design for it.
There are a few reasons for the move. It uses the Flickr API instead of scraping the page, I no longer have to update the page when I change WordPress themes, it’s easier to keep track of resource usage and the domain is easier to remember. It also looks better. Go forth and add it to your bookmarks.