Should I abandon post categories in favor of 100% tags?

I’m seriously considering abandoning use of post categories and going 100% with tags. They are increasingly becoming redundant – look at my last post, where, without even thinking about it I assigned “seattle” and some variation on “Web 2.0″ from both categories and tags.

Tags are just so much more of a useful convention – more social, more flexible, easier to create new one’s as needed on the fly (vs. having to manually edit the categories in the blog engine).

Right now categories largely serve as archival – I just started using tags (see my nifty tag cloud on the Archives page) so the majority of my posts have categories only. To keep the site navigable I would need to go back and retag/de-categorize hundreds of posts, which doesn’t exactly sound like a wildy good use of time. And really, I would venture to say 90% of the time people look for posts on specific subjects on specific blogs, Google – and not categories – is the #1 tool. Technorati and its ilk – using tags in large part – are probably the other 10% and satisfy the broader “what’s being said on this subject” queries.

An option is to rely on categories from broad-grained classification of posts, so at a minimum they are easy for me to find – “microsoft” and “marketing” are two obvious big-bucket categories based on my post history – and rely on tags for the fine-grained sorting.

What’s the general trend? Are blog post categories losing their value with the emergence of tagging as an alternate?