Webcam mounted on /dev/video0 and usable by VLC but nothing else detects it

Solution 1:

Some programs like Skype use the older Framework v4l instead of the newer v4l2. This is not supported by every module out of the box.

env LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so /usr/bin/skype

This way, the older framework is forced to use for skype. I'm not good in explaining in english. Sorry.