McAfee SiteAdvisor is a security add-on for your Internet Explorer and Firefox browser, help you identify sites which are linked to spyware, adware, spam, viruses, browser-based attacks, phishing, or online fraud.

Once installed, the SiteAdvisor service integrates with search engine results from popular search engines (Google, Yahoo, MSN and many others) and also adds an icon to the browser toolbar that indicates whether a site is considered safe to use. It uses different icons to notify that whether a site is secure or contains spywares or other worms.


If SiteAdvisor has negative information for a site, you can review a detailed online report that shows any spam received from that site, a list of harmful downloads and link relations with other sites.
SiteAdvisor’s current version is available for Firefox and Internet Explorer.

Get it from there


Reframe It approaches the idea of Web page comments from a different angle. It puts them in a sidebar that changes for any page you visit so you can comment even if a page has no comments functionality, and there’s no moderation.
Because you start by setting up an account, Reframe It provides a hub to connect all your comments with all your social networks. So it’s easy to bring friends into a discussion, and give them plenty of contexts.


Restart Firefox after installation and you will see a prompt in the sidebar (called the Reframe It Margin) to create a Reframe It account. After that’s set up you can open and close the sidebar. One popular way to make a comment is to highlight text on a page, make a comment about it and post.


Share comments with contacts:


And when you point someone to a site it’s easy to clarify what matters on that site. Right click on an image and choose “Reframe It –Add Comment Here”.


Think of it as a social network that follows you around on the Web. Then think of it as a comment function established by the commentators themselves. Watch this video for clarity.
Reframe it is available for IE and Firefox. Get it from there.

Firefox: Download Here
Internet Explorer: Download Here


This extension allows you to select and open multiple links/images in one go. Once Snap Links is installed on your opera browser all you have to do is drag a rectangle over your links, and click your mouse button to open them in new tabs. Through this you can save a good amount of time, especially when you’re browsing a link rich page, like search results.


Note: Snaplinks is compatible with Firefox 3.0 or lower versions only.

Snaplinks is available for Firefox and opera.

Firefox:  Download Here
Opera:  Download Here


Wolfram Alpha – the most ambitious search engine since Google is a computational knowledge engine, which aims to answer questions directly, rather than display web pages in response to a query.  Wolfram alpha has recently launched its extension for opera. This extension gives a quick access to wolfram search engine.
Once installed, click on the “wolfram icon” and a Wolfram drop-down will be displayed.


This drop-down contains examples, a video tutorial and the search bar where you can input he query. If you are new to wolfram then the video tutorial and examples will really help you that how you have to input specific queries and how you can search more specific results.  

To checkout its power, type any input and it will give you the results within the same dropdown without leaving the current page as you can see below.

 
Wolfram is really a master piece of work and most ambitious computational knowledge engine since Google. You can even calculate mathematics, statistics physics equations directly within no time. If you are a researcher, writing some mathematical thesis, or any report then I think that your browser is incomplete without it.
Mini wolfram is only available for Opera Browser. Get it from there.