I think most people who take photographs have some they are proud off and want to 'show' others. They are not looking for anyone to say 'it's alright But'.  It is just 'this is my photo of this ' and I am proud of it. 

A lot of people look at an image and think I like that, but how many stop to think Why do I like that? Most are just happy to like it and say just that. No more no less.

I leave a comment on photos that stand out for me, sometimes it's the POV, or the Composition, even the mood or DOF. Others I like I don't comment on because they have so many comments mine would be just another number.

Everyone has their own way of 'seeing'  whether in taking  or in viewing a taken photo, some ask for help in this but at the end of the day it has to be their photo and not a photo taken by them the way someone else has said they should take it. Constructive critique on the other hand is asked for to help improve different aspects of the capture in the next photo and an IM to offer suggestions would be IMHO much better than to add it to the photo on show.

I allow comments but I don't allow ratings, It is enough for me to know you like it, why you like it would be nice but how much better than the rest you think it is doesn't do anything for me.  

Just my take on it, rambled on a bit but then again thats me.

Pat