Breaking 0.03% of the web is one thing, breaking larger parts of it starts to have far more dramatic effects. Many of the "worst" parts of the web are some of t

Breaking 0.03% of the web is one thing, breaking larger parts of it starts to have far more dramatic effects. Many of the "worst" parts of the web are some of the most pervasive: well over 90% of the web relies on non-conforming HTML being parsed, much of the non-English speaking world relies on some of the really whacky behaviour around URL serialisation/parsing with different encodings, etc.