It seems most people are missing the point here. This is not simply about silk touch books but any enchantment not to mention the unlimited amount of emeralds and xp if you know how to trade properly. The only reason silk touch books keep coming up is because 3point14mp sold them in bulk and then others followed including those who had bought at what they thought was a good price at the time. If you want to see what effect villagers have on the market you only have to look at the current price of emeralds, xp and maxed tools and lastly silk touch books which btw have been done to death. Villagers make setting up spawners a thing of the past, simply because they generate more xp and make more money per hour than any star tool but then so does sg at the moment.

I love trading villagers myself as it's easy money but I honestly believe it will have a negative effect on the economy and I again point out xp, emeralds and maxed tool prices as proof of this. Compare any of these items current prices to that of two months ago and you will see exactly what I am getting at.

Another edit, This is hardly what you can call abuse. Money makes money right? if someone owns a melon sword and builds a 200 x 200 melon farm are the abusing a melon sword?