I have an e-commerce website. In my website there are two types of registered users:

1. Seller
   (They place an advertisement to sell there product [example:house])
2. Buyer
   (Want to buy house of seller using their Bitcoins)

When purchaser wants to buy something, I want their Bitcoin to be stored in my wallet. When buyer get product just he will release his Bitcoins to the seller. To fund the site, I will take a percentage as a profit, and the rest will be sent to the sellers wallet.