Don't be bashful! If you want comments, give comments. You don't need to be an expert photographer to express your opinion about the work of others. You don't need to go into great depth. A simple remark about cropping, composition, color, subject matter, etc. can be of just as much help to a budding photographer as an in-depth critique.
For this assignment, take a macro portrait of a person. The photo has to convey an emotion or state of mind. Try to show as little as possible of the model and still get the message across. Take some time to think about the approach you take with your model so you can get the best results and then post that favorite photo to the Web site.