Are exclusive advertising deals a fair business practice?

This is a question to all of you running businesses out there - you
can check out my ramblings about this on my blog at:
http://xsqlsoftware.spaces.live.com/blog/ Check it out and post your
comments there - I will review all comments and post the majority
opinion in a couple of weeks.

PS sorry for the non-technical question, but we are in the SQL Server
tools market and hence I thought this would be the best audience to
post the question to.

Thanks,
JC
xSQL Software
http://www.xsqlsoftware.com