Responses here actually show how disturbing this topic is. Starting an exchange is logistically and technically a very challenging project. There are compliance and regulatory requirements which need addressed, adhered to and complied with. Then the staffing or manpower element which is a core determinant of any exchange's operational efficiency. These are just some of and in fact the least of requirements to worry about. It's an extremely complex investment and project combined in one.

Software alone is not in itself what one needs to start an exchange... UNLESS some of those who responded here have other (more sinister) motives in mind. By that, I mean one basically creates a fly by night website with all the bells and whistles and impressive trading tools etc. Then this "software" sold here is simply integrated into that website. Voila and the exchange is up and ready. Hot wallet nicely set up... pretty much the website owner's bitcoin wallet. Setting up overnight exchanges is all the rage now. It is seen as the pathway to a quick buck.

And I think I know why offers like this tend to be very attractive: exchanges are seen as a surefire moneymaking scheme and a way to avoid escrow.