Web smarts
"Never send attendees (participants) to your organization's home page. Send them to a landing page dedicated just for...registration. Welcome them on that page and make them feel smart for registering now!"
This marketing tip from Ron Rosenberg is very applicable to races (he consults to associations and for-profit companies). Linking to an event home page is fine, but not to a home page for the organization hosting the event (e.g. running club, ymca, charity, park district, hospital, chamber).
If you force runners to click through pages they don't need or make them search for the appropriate buttons and links, they may just give up and find another race.
If you offer online registration, link directly to your registration page, not to the home page of the online company.