Diigo is the first web service that comes into mind when talking about web annotation. . Diigo has a tool that lets you annotate web pages, add notes and colour specific chunks of a paragraph to share with your colleagues.
This is another great bookmarking and annotating web service. It allows users to save a web page and annotate it the way they want via adding comments in text boxes or highlighting important parts. It also has a social ingredient in it in that users can share their annotated content with each other.
3- Awesome Screenshot
This is one of my favourites. It is a chrome and Safari extension that allows users to capture screenshots of their webpage and then draw on them lines, annotate them, add text and comments, and share them with others. If you are a Chrome or Safari user then this is indispensable.
This is also a great annotating tool. It is very easy to use. Just type in the URL of a webpage and Bounce will then create an image of it allowing you thus to add text and annotate it.You will also be able to share your annotated content via a unique URL.
This is mainly a bookmarklet that you can drag and drop onto your browser toolbar. Once there you can then very easily annotate any webpage you are viewing by simply clicking on that bookmarklet. Again when you finsih adding amd drawing on your webpage you can share it with others via a generated URL.
6- Screen Draw
This is an awesome extension from Firefox that allows users to annotate their selected webpages. Users can circle elements, type in notes, or draw on any webpage they want before saving the annotated work as PNG or JPG files.
7- Webpage Screenshot
This is a Chrome extension that allows users to take a screenshot of a webpage and add their own drawings or arrows.
This is another awesome tool that allows users to create annotated screen capture images. Once you take a screenshot of your webpage you can then add text, arrows, draw on it and highlight sections of text within it.
This a great tool that lets users annotate , edit and share their PDFs, Power Point files, and Word Documents. It is very easy to use and all it takes is you uploading the file you want to work on and select your marking tool and there you go. You can also share with your colleagues.
This is another free web annotation tool for both Firefox and Chrome. It allows users to highlight text and annotate webpages and with a single right click save the annotated work to Google Bookmarks.
This a free tool that lets users place little yellow squares of digital paper anywhere in a webpage.
12- Draw Here
This a bookmarklet that you can add to your toolbar in order to be able to draw on top of any webpage when you are browsing the web.