I thought id run by a scenario ive encountered recently.
A company contacted me through my regional directory site, asking me to exchange links with their client.
I believe the company charges for this service to their clients (they run around finding links for them).
They contacted me previously and I OK'd it because I had a relevant section for that particullar client (and my site may have been of interest to their clients users).
However in this case, their client is a SEO company (why they arent doing their own marketing i dont know - probably run by the same team!) who have a www.keyword1-keyword2-keyword3-keyword4.com name (yes, 4 KWs!).
I have a webmaster resources section on my site (not a very good one though - havent put much work into it! :)), so I could link to them and keep it "on theme".
But their link section is one long list of sites that this recip link company have found (not categorised, not themed, not even in alphabetical order), so Im concerned what affect (if any) that would have on my site.
I considered asking them to deep link to my webmaster resource section (the SEO company is US and my directory is regional UK) as the rest of my directory is irrelvant both to the users of their site and to their theme.
Reading what i have just wrote i think i have convinced myself not to agree to the link exchange!