How does this apply to an Internet Browser Add-on? 

It seems this phrase "web of trust" applies in some way to internet browser add-ons, which is how I came here.  I assume the browser add-on allows a group of people to trust a web-site (or not).  Nor sure.  Someone on a Tech Forum said that having a "Web of Trust" add-on to your browser allows you to know whether or not an unknown web-site is dangerous or not.  It would be useful if this article included some explanation of this.  I'm still not sure what it is exactly, or how the encryption "web of trust" relates to the browser.

99.137.251.249  Jimmy Rapid