Incredible, but true... Most Marathon organizers find that more visitors make it to their website from a link on MarathonGuide.com than from any other source (just ask your webmaster).
The fact is that most marathoners (at least the ones who know about MarathonGuide.com) begin their search for their next marathon on this website. They read comments by runners who have run your race in the past, view past results, read the news - then they often click through to your website.
Login to the Race Directors section to view statistics about visitors to your website and to the MarathonGuide.com listing(s) for your event(s) - it's interesting. For those marathons that advertise on MarathonGuide.com, ad statistics are also available.