How do the Internet chat room providers make make their profit?

Most make there profit from advertising and Pay per click systems such
as the Adwords system here on Google.

Say I had a product I wanted to advertise, One way in which I could do
this would be to create an add Banner and generate some affiliate
links and offer them on my site. Other website owners put these on
there site such as chat rooms, if a user clicks the banner or click on
there site and comes to my product it is recorded on my server, if
they buy an item we see where the buyer came from and if an affiliate
we pay them a percentage of the sale.
Most sites earn there money in this way. Others if lucky are sponsored
but large companys, but not many.

Take a look at www.local-chat.co.uk they have no adverts and provide
local adult chat rooms for every County in the United Kingdom.