Where to find classification and data structure advice
we are in the process of developing a classified ad website due to launch in about a month (yeah i know, this overcrowded market, but we plan to focus on a certain region which is currently under-served and plan to develop that specific market by combining various off-line and on-line methods)<p>and would need some good advice on how to structure the categories (of course this would come down to the market we are looking at but what i am seeking is a sort of general repository or advice) and also what kind of data that should go in each ad to be posted<p>i have looked around at 20+ websites all from the simple title and description settings to the viciously structured ones with lots of choices for the user to fill in<p>so anything that would come to mind or references to such advices would be great