The wiki has a nice page on editor usage statistics showing how many people are using each editor on a year-by-year basis. The data is compiled using data available from this page, where each 550MB archive contains the entire history of changesets starting in 2005.
Because I released Go Map!! about a week ago and the weekly changesets file became available last night I wanted to see the degree to which people are using Go Map!! for real editing. Here are the top editors sorted by number of edits for the week ending Feb 1:
Go Map!! has a very solid showing at position #4 for its first week, and as people become more comfortable with the app's feature set and mapping on a mobile device it seems entirely reasonable to reach 100K+ edits/week in the near future. Clearly many people want to map on the go, rather that at home in front of a computer.
I was surprised at the proportions of the countries downloading the app. While supporting multiple languages would be nice to have, at least in the short term it doesn't seem like being English-only is limiting the user base much:
I'm also disappointed and sorry that a font rendering bug in v1 may make many street names render incorrectly in those Asian countries, and it will be addressed in the next update.
At first most downloads were in the US and Europe, then later in the week Russia and Asia were the largest downloaders. It will be interesting to see at what level download rates stabilize over the next couple months. OSM is a relatively small community and it is hard to predict how quickly market saturation is reached:
Around 1200 people had downloaded the app when the changeset snapshot was made, but only 170 people had uploaded edits, so the rate of use isn't as high as I'd like. Part of this might be due to the font rendering bug that affects non-Roman fonts, disenchanting downloaders in Asia/Russia, and part just because of the relative newness of the app.