I found this app while looking around for apps that can block incoming phonecalls and text-messages.

This is the homepage:
MCleaner for iPhone -- call blocking and sms reject

I'm interested in trying this out, but there's one little line that scares me:
"For the new version needs your IMEI number to register, please send your IMEI number to us."

Is it safe to give out your IMEI to other people?
Or can stuff be done with that number?

Any input will be very appreciated