It is not acceptible, in my opinion, to offer advice unless it is asked for. For myself, if I just can't stand it, I don't leave a comment, or I might say something generic like nice to see you scrapping or some such thing. First of all, if you don't know the person, and sometimes even if you do, lol, you can not guarantee how the written word will be perceived by them. Second, I hate the thought of discouraging someone from posting again, or making them feel embarrassed or unwelcome. If you really want to be generous, and I mean generous,

go ahead and send them an uber-over-the-top friendly note and say, hey did you know...? And then be prepared to sort of mentor them etc. It could be a nice way to strike up a new e-friendship - been there done that, but it could also cause hurt feelings if they aren't ready to hear what you have to say lol. On the other hand, if someone asks for a critique, I have no problem laying it all out lol. But that's me!