It’s one of those topics in English usage that just will not die. It erupted on ADS-L yesterday, with this query from Dan Nussbaum:
In the sentence, “Hopefully, the sun will rise tomorrow” the word hopefully is being used incorrectly. What word should be used?
And then we were off on a familiar path. Larry Horn got in first, noting that there was nothing incorrect about the example; Lisa Galvin reported that she had a professor long ago who said that the proper usage should be I hope rather than hopefully, since as it stands the sentence says “that the sun itself is full of hope that it will rise tomorrow”; and Larry replied:
“Hopefully” is a sentence adverb in such contexts and has been used as such for decades — while also being a manner adverb in “The dog is sitting hopefully by her food dish”. (Not arguing with Lisa here, but with her long-ago professor and my fellow [AHD] Usage Panelists who vote with the majority to condemn this perfectly ordinary and proper usage.)
Pretty much everyone who writes about English usage has taken on hopefully, and the informed consensus is solidly with Larry, but a bizarre irrational prejudice continues against sentence adverbial hopefully.

