Here is the official announcement.

What this does is:

Include a FEED from Google Blogsearch, giving you information about ANY site you go to, and immediate access to what blogs have to say about the site.

Why is this scary? 

This has made it THAT much easier to immediately see "what do other people think about this site/person/product?"

Here's an example from my site - NOTE:  I expanded the listing of comments, normally it's a very small little icon in the bottom of the browser.

Why is this scary?  Well, two reasons -

a. Take a scenario - you want to bash on someone? Simply publish a lot, and perhaps your criticism of a site/person/product will IMMEDIATELY be accessible to anyone with this extension.

It's like reviews on mega-steroids, backed up by Google speed, backed up by the "relevance" engine of Google.

Goodbye to any other review site - why are they needed?

2. If someone develops a way to RATE blogposts,- quickly and easily - and this is added to Google's relevancy engine - then you will get the most recommended reviews/thoughts/ruminations/rants of a site/person/product, immediately.

I have referenced this before - here for Yahoo Local Reviews, and here for The Long Tail.

But this particular Google implentation means that this immediate impact from PEOPLE, and their silly/good/bad/rantish voices, are now embedded in the browser - and Oh So Easy - to get to.

While my focus is practices, and learning functionality, the immediate impact may be on product and product pages - but the impact on people will be felt immediately after.

One thing that will need to be fixed is to EXCLUDE blogposts FROM that site that you are on/looking at, or same person, as this clogs up the "what do others think?" functionality.

How does this get onto Internet Explorer?  Simple - by updating the Google Toolbar.