[curtis]

It's not strictly limited to proper nouns -- try "jury nullification" or "obfuscated code" for example. However, if the matching title is a proper noun, it requires exact case match. This is a side-effect of relying heavily on case for matching in order to prevent accidental or overzealous matches. This is in fact a fairly thorny problem, at least without some sort of semantic parser.

[doubleplus]

hm... okay i typed a few more into the same link and it picked up a couple... i just figured it was only proper nouns b/c those worked every time. thanks...