added paragraph about address reuse

bip-0131.mediawiki

@@ -77,6 +77,28 @@ the user when their wallet contains many UTXOs that qualify it to benefit from
 a coalescing transaction. Wallets should not simply replace non-coalescing transactions
 with coalescing transactions in all instances.
 
+== Isn't this BIP bad because it encourage address re-use? ==
+
+Address re-use comes in two forms: reuse from the ''sender'', and re-use from the ''receiver''.
+
+Re-use by the sender is basically using the same address for the change output. This is generally considered bad
+since people looking through your transaction history can determine who you do business with. When
+you generate a new address for every change, your privacy is conserved as it is impossible to know which
+output is a recipient, and which output is the change output. This BIP has '''no effect''' on re-use
+by the sender.
+
+On the other hand, address re-use by the ''receiver'' occurs under completely different circumstances.
+When you publish an address and have multiple people send to that address, you are engaging in address re-use
+from th receiver. This activity has historically been considered bad because it leads to re-using a private key.
+When you re-use a private key too many times, you run the risk of somebody performing statistical analysis
+on the multiple signatures, which can lead to an attacker finding out your private key.
+
+This BIP introduces a way to spend multiple inputs without re-using the private key. In a sense, this BIP
+fixes the problem that makes address re-use bad for the receiver. After this BIP becomes implemented
+and deployed, address re-use by the receiver will no longer be considered bad form.
+
+
+
 ==Copyright==
 
 This document is placed in the public domain.