tedster - 9:21 pm on Mar 13, 2008 (gmt 0)

I've been involved in several "clean-ups", many of them involving a new set of pages, and some a complete redesign. As long as you're maintaining the same domain name, then you can re-invent your site with little or no loss in traffic, as long as you do it with precision.

I think the key, in addition to technical precision, is not to change urls unless you absolutely can't see another way. In those cases, do a study to see if you really need a 301 redirect to take care of pages that are getting good search traffic or have strong backlinks. Only set up a 301 in those cases, and let the rest of your old urls return a 404.

Just make sure you've got a good linking structure. That alone helps Google sort out your revised site. Without a pile of 301 redirects to chekc for trust issues, Google can handle the revised site pretty quickly.

And speaking of a study, I'd really look closely at the traffic to those category/brand pages,including whether those visitors convert. That kind of page can really be a useful thing for some sites.