1,000,000 page site rebrand - new domain, new urls

[union_jack]

I am currently working for a SEO company and have a important client that generates large amounts of traffic in Google, unfortunately they are rebranding as a company which means change of url. I have never done a site on this scale before(1,000,000 pages) so i could do with some advice.

To complicate matters they really need to change some of the site structure too. ie current

www.domain.co.uk/letters/numbers/index/keywords/id/idnumbers

I want to trim this down or at least make the directory structure more seo friendly.

My first thoughts are to launch the new site and gradually 301 sections of the old site to the new over a period of time. I know there could be duplicate content issues but my experience says Google will just show the most relevant page and not give any penalty. But as it is such a large site, who knows...

[tedster]

There's a good thread about moving to a new domain in the Hot Topics area [webmasterworld.com] - Moving to a New Domain [webmasterworld.com]. That thread includes a link to a Google Blog post from last summer that lays out their recommendations, which do include moving one part of the site at a time and keeping control of the old domain for at least 180 days.

Rebranding to a new domain can be a very sticky problem, especially if you also want to change the url structure at the same time. That part alone is a lot to chew on - see [webmasterworld.com...] (also in hot Topics).

Getting existing backlinks changed over to point directly to the new domain - and getting new backlinks as well - should be part of the plan. The rebranding alone should be one way to attract new links.