Answering questions asked in the comments by writing a reply or an email is also useful to get better feedback from visitors. And it is polite too. But I believe most people do this anyway...
Critique can be useful, however one has to know where it comes from. Even the - apparently - much appreciated feedback from onexposure is not more than a personal opinion of someone. It is helpful to be criticised by a photographer whose work one admires but it is also important to know what one wants in photography and then develop a self-critical attitude.