I have seen people already selling logos, account verifications, upvotes and art. I am sure people are already using to get people to do stuff (i.e. paying for services).
Escrow services could become a big part of the platform and online shops and vendors will definitely want to use it to create a window to the world. They may use another currency such as bitcoin to settle but Steem has many more advantages over bitcoin and could well become the currency of choice for exchange.