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.
Blur your image by panning — that is, moving your camera in concert with the subject. (Note that panning works best when your subject is parallel to your camera’s digital sensor.) Be sure the subject you choose is colorful, as is the background. Experiment with different shutter speed/aperture combinations to get the effect you want. The scene often reveals what combination will work best: a sharp pan or a blurry one.