I think Vannevar's idea has merit, but with one or two tweaks.
It seems like sweeping out the monthly report would help keep the database from getting cluttered, so long as there is another 'page' so to speak, with all the cumulative reports since The Dawn Of Time -or more likely, the past few years.
I think an overlay as such could eventually be assigned sectors (of the city/county) and/or maybe more focal points such as intersections, designated by color, for quick reference. Red would be signal an area or point with a high density of incidents, and so forth.
The benefit of course would be that any cyclist would have enhanced situational awareness when planning or executing a route/ride. Event planners might even use such established data to take special precautions, incorporate more safety/volunteers at 'red' areas/points.
I think if done properly an app could also incorporate a user reports section, where actual cyclists can provide specific information that other cyclists need, such as glass all over the road, malfunctioning signal lights, etc. The caveat being that comments would have to be regulated, as to be perfunctorily brief, a la Twitter, so the users don't suffer from TMI.
Of course you must name it, and that's half the fun. How about Biker Buddy, iBike, or Pedalphile? 