The Web of Trust (WOT) Chrome Extension does the first steps for us. I stumbled upon it a couple years ago and recommended it to everyone. Then one day it was gone. I have recently discovered it is back and I want to spread the word again.
The extension allows everyday users to rate websites based on trustworthiness and child safety. Of course, you have to take in people's objectiveness and ability to accurately rate a website, but overall I have been very pleased. A green rating indicates the website is trustworthy, a yellow rating means to be cautious, and a red rating is danger.
Here is the WOT extension in action after searching for 'Martin Luther King Jr.' You will notice that after the website heading there is a circle that shows you the rating. If you hover over the circle it will give you the rating based on trustworthiness and child safety.
If you are shocked to see that the martinlutherking.org website is flagged as dangerous, you are not alone. I have used this website in many professional development sessions to demonstrate that you can't believe everything that you read. When you dig into the owner of the website (Stormfront) you discover that it is authored by a white supremacist (Don Black) whose agenda is to spread lies about Martin Luther King, Jr.
In addition to the search warnings, you are prompted with a pop-up if you go to to a website deemed as 'dangerous.' The pop-up shows the rating, identified issues with the website, as well as a link to see additional details and comments.
I highly encourage every teacher to share this resource with their students.