Rugs can get damaged by any furniture you place on your rug. Common damage occurs from furniture weight and when furniture can be displaced. In either case the carpet pile is ruined. Most damage can be prevented using simple methods.
The most direct way to take the weight of furniture off your rugs is get an underpad. Pressure bearing underpad will even out weight distribution so that it is not centered on a small area. Another thing to do is get padding cloth for under furniture legs and corners. This will also remove weight pressure.
If your rug is damaged from furniture there are possible corrective methods. Wool rugs can benefit from steaming the area and lightly brushing the pile. If the rug fibers are thinned or worn, rug repair will be necessary.
Overall, it is good practice to rotate your furniture and have your rugs professionally cleaned annually. This will allow weight bearing areas on your carpet to breathe.