Teejay23 said:
As an admin or any staff member at that. Is that you are there for support and a representative of the forum you are with. On top of that you are a role model to other members.
You should not ignore messages, if by chance you are very busy and the message will take long, just send a quick im sorry ill get back to you soon reply.
At least you acknowledged the pm and the member has been notified knowing it will be looked at.
If by off chance you are getting 100s of PMs and cant reply all. Post a message on forum stating it will be abit to reply. Constant communication is key to success.
The part I bolded is what I usually do. I'm usually pretty good about replying to a person's PM right away, but on the rare occasion that I can't for some reason, or if they're requesting something and I need some time to think about it before giving a definite answer, for the request, I might say something like, " I really like your idea, but I am really going to have to think it over first and see if it will work well for our forum." or something along those lines. Also, not sure if anyone's said this yet, but you should always be polite when you tell someone you are unable to get back to them right away.