There is a recent fad for Japanese schoolgirls to send each other messages in basically Japanese schoolgirld l33tsp34k. The problem is that, despite this being very trendy, its very annoying difficult to do well on a cellphone. Enter a web service which, if you send it a mail, will l33tify it for your friend without having to do any work. They then charge your phone bill about 5 cents. (Figure on 2 cents going to the phone company, incidentally).
Sounds like a complete waste of time, right? Yeah, probably… unless you process 20 million messages a month. Which apparently one of these companies is doing. For a service which is, approximately, a 15 line Perl script and a 100 line Japanese-to-gibberish table of rules.