Im looking at potentially buying an established forum with 20,000 members and 350,000 posts. I do not think the Domain is optimal to what the forum niche is. The forum is at this point is pretty slow and almost dead hence my chance to buy. My question is if I change the domain name what is the best way to go about getting all fo the pages re-indexed by google? Its vb 4.0 Thanks
Change the domain in the admincp --> options --> url Once changed, get your sitemap resubmitted, to google/yahoo/bing etc they will re-index everything for you just fine.
If old domain is still with you, do permanent redirection for all links from there to new links, soon search engine will replace old links with new ones.
Even if you submit the sitemap to google, it may crawl all the pages, but wont index all of them right away. It may take a while. How about moving to the new domain and let the google crawl the pages and let your users know that you are moving to a new system. On one day bring all the changes from old system to new system?
It's a big job. your best bet, with the highest amount of retention for index placement in google is 301 redirects, as mentioned by mastermunj. The main thing to avoid is losing juice from existing backlinks and also making sure you don't end up with indexed results in google that go to dead pages