There are some people in the group that I ride with that call out every crack in the road... I try to stay away from them, for fear their constant calling out will distract me and I'll hit them (or someone else)! Use hand signals... at least for stuff in the road.
Pam your comment made me chuckle. Both DH and I were once dropped by an inline skater going up Oak Hill in Harvard, MA. This is a major training hill for roadies. And the guy was as least as old as me. I could see dropping me, even though I was not going 5 (maybe 9-10?), but dropping DH, who was a little ahead of me . When I met him at the top of the hill, DH was like, "What the hell was that?" It was hard to tell at first, since the guy was wearing a bike helmet.