There's quite a few agencies, which maintain a facade of being a private person or couple renting out a property and listing a dozen or so properties on one account. The presentation of the data could have been a bit more slick & accessible, the labels are huge. For instance, presenting the data as an evolving heatmap with total properties per neighborhood, cumulative listings over time etc
Agencies with multiple postings, presumably.
"Of all London's Airbnb listings, 41% belong to hosts who are listing more than one rental, according to Inside Airbnb."
http://uk.businessinsider.com/statistics-data-airbnb-rent-pr...
There is an obvious lack of data cleaning here. You can see from the first places drawn on the map that a lot of them are duplicated. I don't think that many people have multiple dwellings in the same area.