Leave a message with the ICC account "suggestion". For example:
message suggestion Add a tic-tac-toe option
We welcome all suggestions to make the ICC a better place for chess
players! We have a long list of suggested improvements that we are
working on now. Please don't feel bad if your suggestion isn't
implemented quickly. Due to the large number of suggestions, we are
not able to send a personal reply to your message.
New features on ICC will often be announced in "news" items.