It only makes since to me too focus on Google then the others because Google will end up being the way a tech savy customer researches your dealership.
mhilger,
No offense intended, but I think you showed up to the game at the 7th inning stretch. Tech savvy customers have been researching dealerships using Google, Yahoo, Bing, Dogpile, Alta Vista, Ask, alltheweb, hotbot, live, gigablast, aol, lycos, youtube, facebook, and countless other engines for a long time. Maybe the future tense in your post was unintended, but this long list of alternative search engines was not.
What do Managing Your Money, WordPerfect, Lotus 1-2-3, PageMaker and Prodigy have in common? Maybe Quicken, Word, Excel, Quark, and AOL will jolt your memory. Every one of these products had a commanding and seemingly insurmountable market share lead that disappeared remarkably quickly. Lotus 1-2-3 dropped from 70% marketshare to 20% in the 4 years that Excel climbed to 80% penetration, Prodigy dropped from 60% to under 10% from 93 to 97 while AOL grabbed a 60% share.
I know that today Google is synonymous with search, but history would strongly caution against carrying all your eggs in one basket very long. Besides that, 10% of the search market still represents an awful lot of eyeballs.