I'm considerably smarter than Greg
and I too have written extensively and given seminars on rubs. I have learned over the years, that there are only two types of rubs that have any value-signpost rubs and traditional rubs. The rest have little or no use in terms of killing a deer.
A traditional rub, one used year after year and usually by many bucks is valuable in terms of indicating bucks are in the area and use the area on a regular basis. The traditional rub is a prime method of "mass" communication between bucks. Just what they communicate, I'm not sure.
The signpost rub, when found in a line is the most usefull. Just as the name implies, a signpost rub provides information such as creek, fence or road crossings, entrances to hidey holes, areas to stop and scent check fields and most importqant, the travel trail for the seeking buck in new territory. These trails are often used only in pre-rut and rut and may not be seen without these signs to tip us off. In addition, the pheremones deposited at signpost and traditional rubs may possibly help stimulate the approach of the rut.
The more mature bucks on a specific piece of property, the more rubs you will find. A mature buck may make up to 50% more rubs. So if you are seeing a lot of rubs, regardless of size, be happy. Just learn to recognize the two important types.
Other than those two rubs, fuggedabouit.