There are several solutions to this.
One is to use a SEPARATE ICQ which you use on your webmaster contact page. This separate ICQ address is set up WITH an Auto-Responder that nicely states that your affiliates must introduce themselves ...followed by your REAL ICQ address. The affiliate reads your instruction/request, then proceeds to contact you via the real ICQ you normally use.
An example would be
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Hi, thank you for promoting BiminiBucks!
Please contact us directly now with your name and your site name on ICQ# 12345678
and let us know how we can help you grow your business.
Please understand that passwords are issued sparingly and only to serious webmasters.
We are online right now so contact us directly at ICQ 12345678
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You can change the wording of course but I think you get what I am saying.
Kroy