@krynsky: We already have the functionality for providing custom lists as RSS or PFLOP. Take a look at my RSS feed for things that I've tagged as "cool":
http://www.productwiki.com/user__erik/lists_rss/gbl-tap-cool/When you click on the tag cloud labelled "My Stuff" on your user page, you are able to filter your stuff. For each tag, there is a PFLOP and an RSS feed.
I think what silence is asking for is a level above the tap to categorize your tap/tag labels. I see that del.icio.us does something similar.
I like any ideas around giving more control to the user surrounding there user page. Make it easier for them to navigate the stuff they've tapped. Right now, it can be difficult to find stuff, especially older items.
How do you feel about having the product categories automatically show up on your user page for further filtering? (In proportion to what you've tapped) For example, you will see "digital cameras" or "robots" and then you can do things like look at all "robots" that I "love". (I love almost all robots, btw)
Love the suggestions, keep 'em coming!