Some websites and blogs are prevent the user from using the mouse right click functions. In some other websites, the keyboard shortcuts such as Ctrl + C also disabled.
Nowadays use of mobile phones and mobile browsing is increasing every day. Most of us are using the inbuilt mobile browser in mobile phones and many of us know about the Opera mini browser, to browse the internet in mobile.
There are thousands of add-ons available in the Mozilla add-ons website.
Here is the some of the best add-ons from my experience.