If you donate, you are giving your money willingly to a cause. The cause being that this server will not live without donations. Because of this, 'perks' were given to donators as a thank you for donating. For example you don't donate to stem cell research for a badge, do you? Of course not, you donate to help people.
You still have perks, just stone ranks can now earn some variations* to the donator perks.
*Variations - Stone ranks for example cannot get purple or blue glass, as those are donator glasses, but they can get say orange or light grey glass if they play on the server enough.
Another thing that most people forget about when they donate is that stone ranks cannot join a game right after leaving one; they have to wait about 30 seconds. This cool-down constantly bugs stone ranks relentlessly, but it is something you don't have to worry about.