Got some email and private messages how there should be some magic "one liners" that can rewrite all the 404s "file not found" errors when all the URLs of a forum change when they remove vBSEO.
Some, oddly enough, who have no experience with vBSEO (or rewriting all the URLS of a forum with a half a million pages indexed in Google) seemed to find my very clear explanation of how to change 404s to 301s cryptic, as if their is some "magic bullet" that works for all forums.
In my original post, I gave "the core examples" (from the now defunct vBSEO web site) about rewrite URLs for forum threads. There are three different examples based on three different vBSEO configuration.
However, a forum has a lot more pages than "threads". There are forum pages, and forum indexes, and archives and archive indexes, and there are single posts and their are RSS feeds and their are other pages where the URLs were rewritten by vBSEO.
If the vBSEO product is removed, all of these links, indexed in search engines, will break, and cause a 404 error. Each of these URLs need to be properly rewritten based on how the forum vBSEO setup was configured. There are many configuration switches for vBSEO, so there is not one "magic bullet" mod_rewrite rule which will work for every forum. Even 100 rewrite rules for our forums will not work for another forum because their configuration is different.
So, having said this; I outlined how to correctly do this; and obviously the method I outlined worked because our forums (this forum) has actually seen an increase in traffic and (so far) no negative SEO hit after removing vBSEO. Our traffic has increased since removing vBSEO.
Did the traffic increase because we removed vBSEO and there was some "magic bullet" one or two liner mod_rewrite rule that magically worked for posts, threads, forums, index pages, archives, print friendly pages, archive indexes, forum indexes, and more?
No, removing vBSEO without careful planning and observing 404 errors and then writing mod_rewrite rules to insure the old vBSEO URL were correctly 301'ed to working forum pages is not a trivial task.
This is why many people who have removed vBSEO and tried to use a quick "one or two liner" mod_rewrite rule have seen their search referral traffic drop. That is not what happened here. Our search referral traffic has actually increased since removing vBSEO because of careful mod_rewrite rule implementation via the technique outlined in earlier posts.
And don't forget that it is important to property use the canonical directive when doing a move like this. Search engines need to know that pages with duplicate content (old URLs and new URLs that point to the same content) have a pointer to the "authority" page, the canonical page