My sympathies, I lived in Munich 15 years ago and it was a nightmare to find a place even back then. I've heard it's only gotten worse. We (Nestoria.de) aggregate listings of most of the players in real estate in Germany (IS24, immowelt, immonet, süddeutsche, others) and offer an API. We also offer an API of price trends (ie what the avg rent is in an area and if it's going up or down). Enjoy: http://www.nestoria.co.…
Thanks for the link, your site is brilliant!
In seriousness though, while we do try our best (not just in Germany, but eight other countries as well), the situation he describes is one that the internet doesn't do a good job of solving. Basically demand way outstrips supply in cities like Munich. As a result, if you have a good flat or house you want to rent out, really all you need to do is tell 5-10 people and via word of mouth you'll very quickly have more than enough high quality applicants. You really don't need online tools.
An interesting result is that we're now starting to see start-ups that reverse the model. In Köln/Düsseldorf there is https://salzundbrot.com (a Nestoria partner) who are free for owners/landlords, but charge applicants a small fee to make contact. Will be interesting to see if it catches on.
The reality though is there is just way more demand than supply. Normally that would be solved by price rises, but the rate of rent increases is reguated by law.
All that said, while I have sympathy with Munich renters, I now live in central London, where the problem is at another order of magnitude. As I always say "London isn't expensive, the rest of the world is cheap".