I appreciate the good news from Google, but I've often wondered why PDFs are so important in 'academic and scientific circles'. It seems that some sort of HTML solution would ultimately work better. It's certainly a very flexible format, easy to annotate, and easy to search. I'm often frustrated by the the difficulty of searching a large collection of PDFs or providing clean annotations when I'm reading papers. I still looking for tools that are good at both of these things.

Why don't we use HTML or something similar for making papers available?

In any case, thanks Google.