WordPress SEO – thousands of new URLs?

I have a relatively new self-hosted blog and have so far posted about 40 entries. I have installed the All In One SEO plug in and configured accordingly.

My problem is that WordPress is generating thousands of variations on these 40-odd posts, differing by querystring parameters. Here’s an example:
https://www.wednet.com/blog/2011/10/07/do-us-a-favor-dont/?utm_source=rss&utm_medium=rss&utm_campaign=do-us-a-favor-dont

The actual post is at:
https://www.wednet.com/blog/2011/10/07/do-us-a-favor-dont/

and that second URL works just fine. I use an SEO service and it is reporting thousands of URLs of the initial form above as using “overly-dynamic URLs”.

What are these URLs and is there any way to surpress them?

Thanks.

Mark