I am interested in developing a website that is similar to 'elance' but for a particular vertical. Is there an 'off the shelf' platform you can recommend for getting started with this, or would I need to develop this web service from scratch? When I write 'platform' I am referring to things such as 'shopify' for e-commerce sites, or 'ning' for social websites. I want to create a multi-merchant professional services site. The site would need to support functionality such as: allowing merchants to open and manage their own profile. merchants would accept payments from customers through the site. file transfers between merchants and customers. merchant ratings by customers.