Several years ago I submitted a huge amount of articles to a article distribution site and got great page rand then it fell off and got it back up again using another article distribution site, Now my pr us leveled off even though I am doing the same thing so I wonder what is going on.
What works in the past wont always work. In order to stay ahead of the game you need to find new ways to promote your sites.
Thats the drawback of article submission, you gotta keep doing it, otherwise it gets burried as the new articles come in
What might be happening is links that were giving your articles PR have been removed as sites that link to them come and go. Are the articles on subjects that were hot at one time and not now? Just a thought. Also, I invite you to submit some high quality and original articles to my article directory. I would love to read them. They must have been pretty high quality if you received "great PR" from them. Remember, quality and originality.
Unfortunately, this is true. Constant diligence is required. No free lunches here....or anywhere...just hard work.
Google and the internet in general are continuously changing. I wouldn't be surprised if what works today doesn't work tomorrow. You just have to adapt to all the changes and find new ways to improve your sites...there are always loopholes...you just have to find them.