I changed my wordpress blog's permalink structure from category/postname to postid/postname by mistake. I know it's dumb, but I could have sworn I was working on my new blog. Anyways, Google and Yahoo have indexed a large percentage of my blog's inner pages with the new permalink structure during that time and I changed it back to to the original setting (category/postname) a few days ago.
Looking at the information from Market Samurai, I am losing ranking for many posts that have ranked in the top 5 on Google for their respective keywords. The posts that used to rank 1 and 2 on yahoo still retain the postid/postname permalink structure and most of them no longer rank anywhere.
I guess what I'm trying to ask is, have I fudged this up for good? Will my older blog posts that used to rank well ever regain their rank in the serp?
You probably have to reoptimize some of the posts in order to regain the lost traffic. This is just temporary though, as the SE will gradually go back to your current permalinks.