Silverlight shows just a blank screen (or Netflix error 1001)

When you've installed Pipelight and notice that the Silverlight plugin window is just a blank screen (but the popup menu works as excepted, and you see the correct Silverlight version there), one possible reason is that you're missing the ttf-mscorefonts-installer (on Ubuntu, but other distros should have a similar package) package or haven't accepted the EULA.

To check if you have the ttf-mscorefonts-installer package installed use:
dpkg --list | grep ttf-mscorefonts-installer

To check if you've already accepted the EULA:
debconf-show ttf-mscorefonts-installer 2>/dev/null | grep "msttcorefonts/accepted-mscorefonts-eula:"

In case it is not installed yet OR you haven't accepted the EULA (...: false) please use the following command to reinstall it:
sudo apt-get install --reinstall ttf-mscorefonts-installer

You should be asked if you want to accept the EULA during the installation process. Use TAB to select the correct button and accept the license by pressing ENTER.