I’ve been having issues with my WordPress installations automatically changing old posts to today’s date. Also, it seems that old posts are getting reposted with the right original date, but the wrong year. This makes them show up as the lastest post. I’ve been Googling forever, but can’t find anything. I thought it was because I upgraded WordPress to 3.0.4. 
Finally I come a across one comment that sheds light on it all. The answer is right below the first comment.
Turns out it’s my own fault. There was a setting in the plugin SEO SearchTerms 2 that was set to “Promote old post with no search engine traffic”. Once I turned that off, everything was well again.
So if you’re having the same problem, check your plugins to see if a setting is trying to promote your old posts. That should fix it! Dummy me.
Thank you so much for this!!!! i AM SUCH A DORK AND DID THE EXACT SAME THING AND SEARCHED EVERYWHERE WITH NO ANSWER!!! I would have never figured this out lol!!!
great work
Thank you so much! I had the exact same problem! Stupid plugin…
Thanks, I guess that’s my problem too! Hadn’t got around to reading about SEO SearchTerms 2 and although I remember reading it in the general info. it hadn’t dawned on me either!
Doh…..!
Thank you very much..
many thanks!
Was having this same problem posted to reddit and a couple other places. I think everyone thought I was crazy. LOL Thank you for posting this!
Thank you! I was having the same problem but couldn’t locate the source. I thought it might be a plugin but didn’t know which one. Now I do. Thanks again!
Thank you very much. I was also trying to find relevant info to this topic. I was searching for “date rewrite”, but nothing found. Finally, I found your article and solve this problem. I have more than one wordpress instalation, so I quickly realized, which plugin was not in other, so I checked it (it was GD star rating) and it worked.
Thanks for this post ! Had the same problem, but not anymore thanks to you 🙂
Thanks a lot for this hint, it solved my problem on http://controlbit.de I was serching a long time for the reason of the date change 😉