The events that have happened here today marks a new era for the internet. Websites that derive their value from user-submitted content are continuing their move towards sealing off that content and information from the world. Their libraries were created by everyone, but will soon be available to only those who pay.
My greatest advice to those concerned: Start archiving. If you come across something you believe is valuable: make a copy.
If you follow a guide on how to install and configure software and you found it helpful: make a copy.
If you come across a video you really enjoy and find yourself coming back to again and again: make a copy.
If it means anything to you: make a copy, or you'll wish you did.