Some websites have those annoying advertisements on them (not that my blog is abstained from such...trying to make a little extra money) that can be a distraction for students in your classroom. inFocus aims to help with that problem by providing users a SIMPLE and EFFICIENT way of highlighting the important parts of websites and darkening the least important parts of websites.
With inFocus, you easily drag the bookmark tool to your toolbar and when you come across a site that you want to highlight, copy the url and then click on the bookmarklet. Paste the URL and you will be ready to highlight the area you want to showcase. It is a great tool to focus on certain areas of a picture as well. If you use Google Chrome, you will need to get the extension HERE.
Here is a sample image.