Tagging content is work of the worst kind – Production Work. Yet hundreds of thousands of people are doing it every day on the web. Apps like Flickr and Del.icio.us have gone a long way to show tagging can be worth the trouble… Now we need more apps that make tagging less trouble.
Yahoo’s My Web 2.0 has the best interaction I’ve seen:

Two things stand out here:
At the other side of the spectrum, Robot Co-Op’s All Consuming has the worst implementation:

Comparing it to Yahoo:
comics supernatural archeology superhero warren ellis. When entering the second book, I had to type all of that again. Then I wised up and copied it to the clipboard for the third book. Except the first was tagged with “comics”, while the second and third used “comic”.Yahoo reduces the mental load required to tag items. All Consuming does not. While adding an extra layer of confusion on top due to the awkward mental model presented by “Popular Tags”.
I think of saving things to My Web 2.0 as a quick and easy process. I’ve used Del.icio.us for links since December of 2003. I still do, but MW2.0 has moved in to handle all my web development links.
I like the idea of All Consuming. I’d really like to have my list of items on my personal blog. The inconveniences of it’s interface (it’s worth mentioning that they go beyond the tagging widgets) seem somewhat minor, yet I haven’t been back. It feels like too much work. With all the other things I can do online, work looses.