What is this, 2004? Link exchanges are just another way to try to take the work out of gaining links and earning trust by swapping links with another site.
Can you think of a more easily detectible signal that you could throw at a search engine to let them know you're trying to get cheap, useless links?
Think of a link as an endorsement of sorts. A link should mostly be used when it makes sense and can help the visitor by pointing them to additional resources or related material.
If someone makes good content then that will help your readers or site visitors, then by all means link to them. That works the other way around too: *hint* *hint* ajmalseotips.blogspot.com
