OldFriend, I'm having the same issue as you on an old site.
I just happen to check one of my page titles to see where the article was ranking and i noticed a title that looking identical to mine (because it was) It turned out it was a complete copy of my sites content. This has been going on for a while I just happen to catch it now. Unlike old friend I'm fighting to take the pages done and hopefully the site since they have basically script a few sites content.
Here is how im searching for my articles and finding the content.
Use a quoted search "Your Title Here to get the best results"
then you might have to click the bottom link which says show X amount of related pages.
Sometimes try Use a quoted search with your domain name minus .com "Your Title Here to get the best results" domainname
What actually confuses me is this site has done everything your not suppose to do or at least what these updates are suppose to block
-They bought an expired domain name with incoming links to a totally different site theme. - They scraped complete articles with same titles *From multiple sites -They rank higher for the "quoted title search over the original article" - What Is even worse its not like these articles were just published articles,these are a few years old. And we are getting out ranked and in most cases looks like discredit for them
I'm looking into some of the ideas tedster mentioned.
What is interesting is a few years ago i set up an alert that posts to twitter for a forum, but not the articles. Which in a sense gives you a confirmation from them saying this article was published on x date from this site.
We also publish an rss feed, which might be an issue i think tedster mentioned in another post.
@oldfriend do you have rss or xml feeds people can use?