The 2 problems you see with zip codes I see as pluses. First everyone knows the zip code they live in, where as the city you live in can be left up to interruptation (I currently live in an area that can be postmarked as 3 different cities without any effect on the mail getting to me and that is due to the zip code not being left to interruptation). Secondly when I do a search for something locally in google I always put the zip code not the city name. Why? faster to type on my computer and cellphone. Which is another reason, instead of someone looking for a professional that is "close" to them. The search results actually are determined by the professional choosing the zip codes they want to service.

I don't want to get into a great debate as to why I think the zip search works best for the purposes I intend, because no matter what it will be one persons preference and opinion versus anothers. I don't think either solution is wrong personally. I just think the solution we have devised is the simplest and fastest for the user, which of course is an opinion that could change overnight. Me personally, I hate going to a site to look up information for something local and finding that instead of giving them one small piece of information I have to either spend time looking for the link for my state, then my metro area, then my city, when in 5 keystrokes and a click (or 6 keystrokes) I could have the same information tailored for my needs.

Now back to the original purpose of the post.

I'm not concerned obviously with the navigation of the site. I think it is simple, easy to use, and intuitive (always my main goal). My problem is how google and other search engines will be finding the listing pages based on zip codes. I may in fact do a drill down navigational page in the future (once we have enough listings to warrant it). But until then I just need a solution that will let the search engines "land" on the listing pages since it seems they won't follow the search forms action url without default data (which just can't be done for obvious reasons). I could very easily return a drill down page when no zip code is submitted or when invalid data is submitted, but that seems useless to work on if the search engines will not follow the action url anyhow.

I also don't want a huge link page with every zip code listed on it linking to the search results, because it really serves no purpose to the users of the site. But if I add a search result zip code link to the sites sitemap will google or other search engines take offense to not seeing that link anywhere else on the site, since it is basically a search result page. Or should I even be concerned about that?

Now that I think about that also, it is also very possible that 100 zip code search results could result in 100 pages that are exactly the same. Would google penalize us for duplicate content based on that? My first and only assumption is it would. Would I be better off just looking for a solution that gets google to each professionals unique page on our site, and not worry about having google reach the search results lists?

Sorry for being so long winded, just trying to be as thorough as possible. Thanks again!