need to build a site that can post your classified ad to the top dozen indian free sites based on alexa rankings.
the problem will be dealing with dozens of categories from each site that maybe unique.
a simple user interface is need to filter through the master list of ad categories when a user is picking sites to post on.
i liked the UI for this site:
it only shows a partial list as you start typing instead of the full list with hundreds of items
an option for auto reply with the poster's contact details or ad details can be set to deal with the many responses that may flood in.
a craigslist style provision to anonymise email ids should be made available to all users.
1st multi post is free [try before you buy style] but email and mobile verification is required to limit duplicate registrations.
copy of ad can be optionally mailed back to the user for their records.
fees will be based on number of sites to be posted and duration [e.g. rs. 1/day]
if the free ad site requires login, then registration should be done for new users only
existing users should provide their login / password for each site [one time setup]
obviously payment gateway is required for cards & netbanking transactions.
3rd party logins [fb, twitter, yahoo, google]
admin pages for updating static content like faq, contact us, about us, etc
image uploads should be handled