If you refer to the map, it shows the new rooms-to-let added on that particular day. Rest assured that there were/are hundreds to thousands of transactions per day in Amsterdam. OP used this datasource: http://insideairbnb.com/get-the-data.html
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.
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
AirBnB is a plague in Amsterdam where people rent out their house almost full-time on the service. A lot of concern has been voiced by neighbours and public figures (notably Arjen Lubach, a sort of Dutch John Oliver). The critisicm comes from the fact that Airbnb pretends to be a place for short term rentals and family businesses on the side, but is spiralling more and more into professional agencies renting out houses without much supervision in terms of safety or tax.
I guess most major cities around the world face this problem but this is a nice visualization.
In Berlin, landlords realized they could get three times as much from an apartment by putting it on AirBnB rather than actually renting it to someone. The situation got so bad that it is now illegal to rent an apartment where you don't actually live[1] (with exceptions[2]).
If the situation in Amsterdam is similar to Berlin, this means that every one of those dots[3] is an apartment that locals cannot use. Tourists are, on a way, taking over their city, and those that live there have to reshape their lives to accommodate them. The citizens of Amsterdam, the ones that make it a nice place to visit in the first place, are losing access to their own city.
In my experience hotels in Amsterdam are expensive and low quality. Perhaps if this weren't the case, there wouldn't be such a market for AirBnB. Moreover, tourists bring huge amounts of money to Amsterdam. Without this the city and its citizens would be considerably poorer.
Well, then it might be terrifying for hotels then.
I'm not sure what the overall impact of Airbnb will be on the more low-end jobs. Sure you won't need bellboys etc, but cleaners will still be handy. I remember reading about a guy who had a very smooth Airbnb operation. He had dedicated fixers (electricians, furniture restorers, etc), and cleaners. So all he really had to do was approve random people who wanted this house for a while, and he was effectively making 2x what he would from rent, though this might have been riskier than just renting it out.
The rules for max 60 days in Amsterdam (pre-existing but that seemingly noone respected) are now seemingly effective at AirBnB level, at least in theory:
https://community.withairbnb.com/t5/Hosting/Some-news-on-how...
and that may contribute to change (either increase or decrease) the numbers of "dots" (or maybe not).
The need for cleaning and maintenance is more or less directly connected to number of guests/nights rented, if guests go to AirBnB's they don't go to the hotels, and the SAME cleaners and maintenance people that used to work fulltime for the hotel will start working part time with the hotels and part time with airBnB's.
As long as the availability of AirBnB's actually increases the number of tourists/guests in a given area/city, that is "added wealth" otherwise it is "shifted wealth".
Conversely - since usually AirBnB's tend to be cheaper than hotels and other similar forms of accomodation, it is "shifted wealth with a reduced amount" (the lower price which is "lost" in favour of the customer + the AirBnB commissions that go somewhere else).
As a side effect the same apartment that was rented for a "decent" price to a local is now used in AirBnB, so the locals must pay much higher prices for long term length.
Also, I fail to see wha's so terrifying about that.
In 2015 it looks like 10-15 rentals a day.