Is this stackExchange site an appropriate place to ask for performance criticisms and reviews? For example, if I have a campaign log for a recently concluded campaign, can/should I post a link to it and ask people what they would have handled differently, how they would have approached certain problems differently, or ways that they feel I (the GM, in this case) mis-managed the campaign?
I think that's too general - if you can scope it down to a specific element, then it might make a good question though. Not "Here's my session summary what did I do wrong," but "How do you handle players getting frustrated by puzzles? Let me illustrate with the events of a recent session of mine...."
Bits of actual play from real campaigns are EXTREMELY DESIRABLE both in questions and answers - in an answer, I consider those about 1000% more helpful than people spouting off their opinion of how things might be. I vote up Q's and A's with examples from real life unstintingly. So posting a whole summary for general critique is too vague and unfocused, but I encourage you to do the same in a more targeted way.
My sense is no, posting an entire campaign log as a single question is outside the scope of the site because that would be a very large, complex discussion with multiple facets and interpretations. A forum, message board, or email conversation is probably a better avenue. (You could definitely ask a question about where to find such a place online.)
Two other options I can think of:
Read through your notes and break it down into a series of specific questions and ask those! If one relies on another, you can include a link to other questions in your questions. As mxyzplk says, please do include details from you notes! It makes them more interesting and adds the context that makes for good questions.
You could ask for or create a room/table on the chat page specifically on the topic of discussing your campaign notes. (I think you need 100 rep to create your own.) I am not sure how you would recruit people to it or get them to 'stop by' but that seems like a possible use of the chat rooms.
General campaign discussion chat room has been created.