One of the most prominent users of OpenStreetMap is Craigslist. Craigslist users often use OpenStreetMap to indicate the location of the house / item they are selling. When they dont find the street they're looking for -- Craigslist users have the option to submit a note to the OSM.org notes system.
I've found these notes to be useful, quite often containing information about subdivisions that are missing from the map. I wanted to visualize all the notes submitted through this system. Even though Craigslist does not submit notes using a dedicated URL (although I think they should!), they use a peculiar notes system and notes from Craigslist almost always look like this one:
bounds: (38.0118,-121.943 - 37.9966,-121.9013) http://www.openstreetmap.org/?box=yes¬es=yes&bbox=-121.943%2C37.9966%2C-121.9013%2C38.0118 Map is missing data here. Freshwater Court in Pittsburg CA is not showing up
Notice -- how they begin with "bounds". This suggests that using the OSM Notes API to search for the text "bounds" should give a reasonably accurate picture of notes from the CL system.
I wrote a script to use the API to get this data, and parse it into a CSV ready for visualization -- you can check out the code on github and visualized the 2980 notes that I found using Cartodb. Each dot contains a link that will take you to the Notes page where you can read the full text of the comment.
And this is what we get! Click on the image to be taken to the CartoDB page (I cant figure out how to embed IFRAMEs in diary entries). You can even download the raw data here