I enjoyed this quite a bit. I had read Nikolai's comment back when it was linked in a few discussions and felt familiar with the techniques, but it's really nice to have a detailed catalog with explanations and links :D.

nit re:

    Although designed to help speed up the parsing of 
    XML documents, it turns out they’re also useful for 
    optimizing web-related features.

HTML is syntactically very close to XML in a bunch of ways (cf XHTML's attempt to unify them IIRC?), so it seems almost exactly like the intended use of the instructions based on this description.