There are now similar drills ("armed intruder" drills) in french schools since the attacks of late 2015. I think it would have been unthinkable before.
> most ad-blockers don't actually block ads; they just block cross-domain, spying widgets. Nothing is preventing you from showing a self-hosted, untracked image that's actually an ad.
Most ad-blockers I know of use cosmetic filters, which can hide any element from a page, including self-hosted and non-tracking ads (see https://www.troyhunt.com/ad-blockers-are-part-of-the-problem...). Sadly, showing ads that are respectful to the user is not that easy...
If you're into music you could learn to play an instrument. It can be pretty expensive, especially if you take lessons (which I would recommend at first), and if you don't have time to practice regularly it's probably not the best idea. But it will give you a good reason to spend some time away from any screen, and it can be very rewarding.
As far as self hosting calendars and contacts are concerned, I'd recommend using a caldav/carddav server, I personally like Baikal [1], and Radicale [2] seems to be another good lightweight option. Contrary to Owncloud these two servers do not provide a web interface to check your calendar/contacts, but there are clients available for most platforms, including web clients if you need one.
I've been using radicale, and it's been a huge pain in the ass. It took me days just to get the permissions right (behind Apache), and its interaction with DavDroid and the iOS calendars/addressbooks has been totally baffling. It doesn't help that the radicale mailing list seems to be no more.
Probably I'm blaming radicale for some of webdav's weirdness, but the whole process has been one of the most frustrating computing things I've done in years.
This analysis fails to take into account the popularity of a language. The repository of a library is likely to have more users if it's written in a popular language, and these users will probably report more bugs and feature requests.
Considering this I'm not surprised at all to see that Java, Python and C++ repositories have a higher "bug density" than Clojure, Go or Erlang ones.
I'm not saying that this metric measures language popularity, but that language popularity seems to have a big influence on it. I may be wrong, but that's what caught my eye when I read the article. There are plenty of other factors that aren't accounted for, some of which have been pointed out by other commenters.
