Why common anode?

[daytimer]

I have searched, but can't find the answer.... Why use common Anode and not Cathode on RGB led's?
Conventional thought (to me) is - is common, + is switched.

[budude]

Many drivers have better sinking capability than sourcing (more mA/pin) so that would be at least one reason. Most, if not all of the boards here use switched grounds so you need common Anode devices.

[David_AVD]

Switching the ground makes interfacing the drive transistor to the micro-controller extremely easy.

Also, NPN bipolar and N-channel FETs have always been more available and cheaper (for same spec) than their PNP and P-channel counterparts.

[dslynx]

I thought it was because it's easier to control the source voltage.