I started writing a comment on a comment where Tim Bushell asks :
why shouldn’t they be “red”, “green”, “blue”?
ie. user-defined or neutral.
But then felt it would be better here :
Probably because Google have a database of thousands of email addresses and patterns that they’ve classified into these categories of “social”, “promotion” etc., and with this move they’re basically giving you, the customer, the benefit of that classification scheme.
They assume that if you just want to program your own categories and sort accordingly you’re already doing it via filters.
What probably didn’t occur to Google was that the world is full of people who WANT to be able to define their own categories and filters but never realized that GMail (like every email client in the 20+ years) already HAS this feature.
What’s happening is that just by showing people tabbed email, they’ve suddenly woken everyone up to the fact that your email client can be programmed to filter emails. (Who knew?)
What happens now is going to be interesting.
If Google know how to listen, they’ll take advantage of it, add the ability to define your own tabs, integrate it seemlessly with the existing filter architecture of GMail (maybe improve the UI of that a bit, eg. drag / dropping between tabs) and get to bask in the adoration of having “reinvented email”.
If not, they’ll keep the two systems separate (ie. filter-definition hidden away where most people can’t find or understand it) and not only will the opportunity be squandered, but many people will continue to hate the tabs.