Internet dating is now moving to the mobile phone with US-based services such as MeetMoi, Fast Flirting, Zogo and Love. And according to a story in The Wall Street Journal: "many of the new services have capabilities that online-dating services haven't offered -- such as letting you search for a date in a location you can update as you move around, and letting you chat with other people seeking a date while you're out and about."
However, there are obvious potential mis-uses. The story says:
Mobile dating services also face pressure to prove that they are safe for users and can't be exploited by stalkers posing as daters. To address such concerns, MeetMoi makes its matches without divulging members' locations to each other, and it automatically logs users out of the location they put in after two hours.
One use, or mis-use, not mentioned explicitly in the WSJ article is prostitution. It seems to me that this is potentially a huge market, though its use could be limited by the loss of anonymity involved when using a mobile phone.