I tend not to greet others. But, then I am very quiet, solitary person, so I do not want to be bothered. Here, in Ann Arbor, I do not see many cyclists greeting each other. That may be simply, because it is a "college town", and a lot of those on bikes are college students, and I think that explains it. Most of the time, when I am riding, I get greeted by motorists on the road next to me, or get pedestrians on the sidewalks talking to me (for example, the other night, I was riding home from a meetup.com event, and a woman commented on my Monkey Lights & said she thought they were different & very nice).

All in all, I should probably try to greet other cyclists a little more.