[ec109685]

“Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can.”

http://www.catb.org/jargon/html/Z/Zawinskis-Law.html

I'd add that Chat seems like a modern day corollary.

[jeffbee]

Remember the time Facebook tried to take on Gmail? Neither does anyone else.

[bismark]

uh, I do? https://techcrunch.com/2010/11/15/facebook-email-killer/