When I started out doing this, I thought it would be a lot harder to grab the names. And I thought it would take several months. Frankly, a month isn't long enough and 48 hours is downright shocking.
FWIW, I'm kinda disappointed at how a lot of people here seems to be on your case and downvoting you, when I think the post was quite informative to show how easy it is to acquire usernames from sites, and that maybe companies should rethink the policies.
If it was in isolation, say 'it takes 48 hours to take a username from SoundCloud' then I couldn't care less, but showing it happen on multiple sites and how they address it does make one think.
The post would be informative (only) had he been showing how easy it is to get others' usernames but not actually taking it. I mean, imagine someone wanting to demonstrate how easy it is to kill someone when he's walking on the road.
But how would he learn how easy it is to get other's usernames without actually taking it? He has to run through the whole process at least once to be sure that the process he would share with us works or not.
If you read the whole post, at a few websites he had to email their support, asking for transfer of their usernames. Once they agreed to give in 'next 48 hours', he could have finally said, "No thanks, I just wanted to test how easy it is." You just need the will. I bet all this sharing of info was an after thought.
What are you going to do to protect your accounts now you have that knowledge?