California:  San Mateo County Treasurer-Tax Collector used to link to various private entities online (MapQuest, Zillow, etc....) until I inquired about who to bribe in order for my firm to get the same treatment, and the links quickly vanished from their website.  (just kidding on the "bribe" part, but I did inquire about advertising links).

The Recorders Office also kept a file of business cards from various realtors, abstractors and more until I inquired about why some business were being given a preference over others and their card catalog vanished. 

Funny when you ask about being included on a fair and equal basis, how things change.  I constantly overhear County workers refer people (wrongly) to title firms that no longer exist, have moved or simply don't provide certain services.  Often such people find themselves referred back to me anyway, when the local title companies tell them that they don't do certain work. 

If the county offers  advertising, take it.  I would have, if it was still an option and not something they found liability with.