But Gmail is interoperable with other mail systems and they didn't create incompatible extensions to email (AFAIAA); that's quite different to how IE6 was.
If Gmail required emails themselves to be in a special format that broke other MUA and IE6 wouldn't render standards compliant emails in a way you could read. That would be analogous to what IE6 was up to.
> If Gmail required emails themselves to be in a special format that broke other MUA and IE6 wouldn't render standards compliant emails in a way you could read.
Gmail is as notorious as IE6 was for its rather poor support of HTML and CSS in email.
