[mbrubeck]

Chrome also took a long time to release 64-bit builds to Windows users. They weren't available on the stable channel until Chrome 37 was released in August 2014:

http://arstechnica.com/information-technology/2014/08/chrome...

Compared to Chrome, Firefox had more problems with legacy add-on compatibility, because in addition to 32-bit NPAPI plugins it also has to deal with legacy binary extensions that link to Firefox's internal libraries.

(For further comparison, Microsoft released 64-bit builds of IE8 in 2008, but few people used them at first because there were no 64-bit versions of popular plugins like Flash until years later. Browsers on Mac OS X worked around this by shipping fat binaries that could launch in 32-bit mode when 32-bit plugin compatibility was necessary.)

[yuhong]

Actually, IE has had 32-bit and 64-bit version since the beginning of 64-bit Windows, originally as separate items on the start menu.

[mixmastamyk]

Yep, I used it a few times on 64-bit XP in 2003ish.