I click on Helsinki, and the marker expands without zooming in to show the people there (neat). (because they are all in one spot)
I click on Trondheim, and it zooms all the way in in order to distinguish the separate dots there (since they are not "one"), and I have to zoom all the way out to go back to browsing the other places. When I am just browsing who is where, this was a bit inconvenient.
I don't know if anything should be done, or even can be done, but thought I would mention it just in case.