[geofft]

What would semantic versioning for a UI even mean? What's the API promise?

[xorcist]

It could mean that all applications still run unmodified and can show all the dialog boxes they used to.

That may not sound like much of a promise, but it is. Applications written for GNOME 2.x won't run under 3.x.

[aembleton]

x.y.z

x would increment on the removal of a feature

y would increment on the addition or change of a feature

z would increment on a bug fix