What is the purpose of the sample pictures?
The sample pictures are intended to show what a particular camera, lens and/or accessory is capable of. As people and nature are my primary pursuits, people and nature most frequently show up in the sample pictures. I usually try to include shots that show unique capabilities of the reviewed camera or lens. Specifically, look for a series of pictures of the same subject showing variations in aperture setting, focal length or other features. Since the FOVCF (Field of View Crop Factor) makes a difference in framing, you might need to make a mental conversion to the particular FOVCF of your camera body.
Are the sample pictures post-processed?
Yes. Minimally, they are resized for the web and sharpened. Since downsizing results in a soft but very sharpenable image, sharpening is nearly always added. Because of this, the sample pictures are not intended to show full size sharpness (read the camera/lens reviews for my appraisal of sharpness).
Most pictures are post-processed using the methods outlined in my up to date (mostly) digital workflow page. In general, sample pictures are post processed to correct color, tweak contrast, remove dust/blemishes, tune sharpness ... I rarely change the background blur in the sample images (a common question). Overall, adjustments are usually minor. Again, I am intending to show what can be done with the particular equipment - post processing is part of the equation for me personally. As a generalization, pictures nearly similar to the sample shots should be possible using out-of-the-camera available settings (sharpness, contrast ...).
Are the people your family?
Primarily, yes. They are beautiful (of course, I'm very biased in this regard). Model releases are not a problem. They are readily available. Many of the shots are from our own property as well. I am very blessed.