I have been using the username silvertje for several services and multiple social media platforms for years and people have been asking me where my username comes from. The answer is IRC. When I first came online, somewhere in 1995, I quickly discovered IRC and became an avid user :)
In contrast to current social networking sites and social media platforms there was no way to “register” a username on IRC. This meant that you either had to hope no-one else would use the same name, or have a very unique username, or be online all the time and “claim” your username through persistant onlineness. Being on a 14K4 dail-up connection which cost over 5 Dutch Guilders (about 5 dollars) per hour I had a clear disadvantage compared to the American and Finnish IRC users who were able to be online all the time for free through their universities. So every time I used IRC I had to dail-up, get online, get on IRC and hope no one was using my username. The first username I picked was ‘sliver’ (after the Nirvana song) but that one was taken very often. Then I decided on ‘_sliver_’ but that one was also often taken. Then I chose ‘slivertje’ to create a Dutch diminutive but apparently another Dutch user thinking the same thing. Finally, I settled on ‘silvertje,’ which means little silver in Dutch, which never seemed taken on IRC and I have happily been using it ever since (although I am not on IRC anymore).