Hi all. This is my first post on MN :) Offering E Safety advice to schools is part of my job and as a Dad with children aged 10, 18 and 20 I've been through this before and am currently going through it again. Blocking will only get you so far. As much as possible it's about keeping communication channels open. Trying to know what your kids are up to online is crucial. The best way to do this is to talk to them about it and to praise and encourage them asking you about signing up for any new services. It's not easy, there is little that matches being un-friended by your teenager on Facebook!
There is a great guide from the NSPCC about talking to your children about staying safe online here
www.nspcc.org.uk/preventing-abuse/keeping-children-safe/online-safety/talking-your-child-staying-safe-online/
Having said that activating parental controls is part of the solution. The problem is there are so many broadband providers, consoles, phones and tablets, mobile providers, streaming and catchup services. This site is extremely useful as it covers most of the possible options at home.
www.parentalcontrols-on.org/