tedster - 5:06 am on May 20, 2010 (gmt 0)

it says no one can really do anything deliberate to affect your seo ranking

Not exactly the way things are. Here's what Google says:

Can competitors harm ranking? There's almost nothing a competitor can do to harm your ranking or have your site removed from our index. [google.com...]

Notice the word "almost"? Some competitors have tried and succeeded with some pretty dark disruptive tactics.

What I recommend to clients who want to syndicate content is that they write a shorter version of the article and include a link to the "extended version" which they host on their own website. It's worked pretty well, even though it is a bit more work. But hey, if you've got something valuable to say, then it's worth it.