Hi. I've had my wordpress site up and running for about 3 months. The permalinks structure is set to the following: http://www.sitename.com/archives/123 All my pages seem to have been indexed by Google. I'm considering changing the structure to: http://www.sitename.com/2008/05/29/sample-post/ By changing the preference is the site affected in any way due to the fact I've had them the other way for so long? Also, I have 'All in One SEO Pack' installed. Any recommendations how I should put it to best use? Any help greatly appreciated.
Regarding the permalinks i wonder this too, i had recently had a blog up for a few weeks before setting custom permalinks on it, so too new and early to know how it would affect anything on that one, but in general im curious about this too.
Permalinks are defined as rewrite rules in .htaccess. When you change the permalink structure, you need to keep old rewrite rules so that they still redirect to correct pages.
There are a few plugins available which achieve this Have a look at this one for starts : Advanced Permalinks
Yes it will effect your search engines ranking for a while, but it depends on the crawl rate of google.... if they crawl your site regularly then whenever Google finds the new permalinks, it will index you. Also, you might consider changing the option in Google Dashboard Backend to leave the old 404 away from the results.
To the best of my knowledge, the newer versions of wordpress will automatically redirect you to the latest version. If you are running an older version, then something like Scott Yang's plugin would be good for you.