Maybe if you can implement Captcha to at least stop robots or put some sort of administrative approval for the messages (e.g. holding them in a quo for inspection since the messages are being submitted by annonymous users) this plugin can become an excellent tool for community websites, especially the sites which have a lot of let's say artists, musicians or other popular people as members.
Also, it will be useful to let the members to activate and de-activate the plugin from the front-end for the ones who don't want to be contacted.
Keep up the good work.
The problems with spam has been fixed in version 1.2 as:
1. Form-resend is not possible any longer.
2. Emails are cloacked.
3. It now supports Captcha (CB Captcha 2.1).