Anonymous donations are bullshit
blog.omakasecharity.org
blog.omakasecharity.org
On the other hand, I do think it's a good example to set, especially for those who are normally maligned as "amoral", eg atheist charities in particular have had to learn to do more PR to counter the stigma (completely unearned; again, studies show that more atheistic/secular countries are more generous) that atheist groups have.
That being said, I try not to bring up my donations to charity, unless they come up some other way, but I also wouldn't be doing them if I didn't enjoy doing them, so it again doesn't "feel" like "charity". I feel actions speak louder than words, and it's best to try to set a good example.
I hate calling attention to myself, but the good of the cause has to trump humility.