Some of us less tech savvy people do not check our email very often. Might be worth trying a public comment, although that does also rely on the person checking email or page. Personally I am also guilty of not responding to emails in a timely fashion. That doesn't mean I don't think they're important, I just like to get what I say right - and I'm easily distracted. I guess what I'm trying to say is they might have a good reason for not responding yet, or just be a bit slack like me - so a gentle reminder is probably appropriate.