Looks like Amazon’s in the midst of a rollout of tags on product pages. It’s not the first dabbling Amazon’s done in the technology, of course, since they were one of the backers of Robot Co-op, whose apps like 43Things are all about the tagging.

Being able to tag arbitrary nodes in Amazon is interesting, as you can see from example pages on the site. (Not everyone will be able to view that link until the test is rolled out to all users.) Thanks to Amazon/Web Services whiz Alan Taylor for the heads-up about the feature.

And while I’m sure there’ s a number of practical applications for tagging on Amazon’s site, the first thing that occurs to me is that I want a new Web 2.0 To-Do list application. Instead of creating your own checklist of items to be completed, the list consists of a few bullets such as:

• Tags
• Blue Gradient
• Yellow Fade
• Feeds for Everything
• Ruby on Rails
• Ajax
• REST API
• Google Maps Mashup

And then you can check items off of the list as you roll them out on your site. No need to bother with pesky features like being able to add or remove items on the list, you just keep going until they’re all checked off, and then you’re ready to flip!