Whether you noticed it or not - Google updated their page rank - they did some tweaking to it, but as always just a couple of things to remember.
When you get a note to exchange links -
1) Would visitors to your site enjoy / benefit from the link - if not - trash can.
2) Visit the site - is the link to the links page on the index page of the site - if not - trash.
3) Check out their links page - would some links their benefit your user - are there any that are offensive - if so trash - if no benefits trash.
Have a good one.