Can we blame Microsoft for starting the trend of top replying to emails? Since I had to scroll to the bottom of this pdf to read the original message from Bill Gates I'm going to say yes. That is a terrible usability issue I've have to deal with every day for years which I hate. I'd love to go back to the days of plain text and > indented replies.
There's pluses and minuses to any implementation. I'd guess new emails on top has won out because it makes previews more useful. Dozens of times a day when I get an email I'm able to digest the entire new content of an email from a 2 line preview that fades in and out of excel. Or when I look through my client I can see the first couple lines of each email and quickly find what I'm looking for.
