A tsunami is coming. And it is made up of the opinions of millions of active web users who have something to say about the products and services they buy.

Technology platforms supporting online reviews have been around for some time. What has changed is that we are now seeing the critical mass of users needed to make the conversation significant.

The introduction of Google Sidewiki three weeks ago makes things even more interesting. Here is what you need to know about this new - and likely transformative - technology.

What is Google Sidewiki?

Google Sidewiki is a new social media tool that lets people comment on almost every webpage online. It appears as an add-on to the Google Toolbar in Firefox and Internet Explorer, with a version for Chrome and other browser to follow.

When you activate the sidebar, by clicking on its button in the Google Toolbar, you can see posts from other users or add a comment of your own. Some of these annotations will apply to the whole page, while others will address a small segment of the page.

If you are signed onto your Google account and have Sidewiki enabled, as you surf you will notice that a thin, vertical toolbar to the left of the page will appear and disappear. That's because the minimized toolbar appears when a comment has been made about a page.

How can I get Google Sidewiki?

For the time being you need to go to the Google Sidewiki page and download a version of the Google Toolbar with the Sidewiki add-on. Expect to see it integrated into the standard Google Toolbar download and offered to existing Google Toolbar users in the near future.

How do I add a comment to a webpage?

Making a comment using the Sidewiki is easy.

Look to see if the thin vertical toolbar appears on the left side of the page. (It will only appear if you are logged onto your Google account). If it is already there you can simply click on the '»' icon at the top of the bar and then click the "Write an entry" link that appears at the bottom of the conversation.

If a comment has not been made on the page before or you are not signed in, you will need to click the Sidewiki button in the Google Toolbar. This will open the Sidewiki area, where you will either be prompted to login or, if you are logged on, to add your comment using the blank comment box that appears.

How are comments ranked?

Much like Google searches, Google will use a complex algorithm to determine which comments show up first. The website owner always has the option to post a comment that will appear at the top of the list. After that, factors like the credibility of both the post and person making the comment will determine the order of comments. Users can also vote on the usefulness of a post, which Google wil then take into account when ranking comments.

(It will be interesting to see if Google starts to assign reputation rankings to Sidewiki users, similar to the Pagerank they use for webpages, to help them determine which posts should come first.)

What if someone says something negative or untrue about my business?

Unfortunately, there is little you can do to remove objectionable comments from the Sidewiki, as only Google or the person who posted the comment has the ability to remove an entry.

As a business owner you can claim your site and add a post that will show above all other entries. (The process is explained below.) You can also encourage others to make positive posts about your business, which can diminish the impact of negative comments.

If you encounter an extreme case of defamation of either yourself or your business, you can consider using traditional legal options to protect yourself. Users must be logged on to post, which helps remove the anonymity of the person making a comment. All users must agree to Google's content policy, which prohibit things like abusive comments and copyright infringement.

Can I comment about my own company?

Yes. In fact, when you claim ownership of your website and make a post as the company owner you have the option of having one of your posts appear at the top of all entries on the page, highlighted by a green background.

How do I claim my site in Google Sidewiki?

To claim your site you need to do the following:

1. Create a Google Webmaster login if you don't have one already.
2. Login to Google Webmaster tools and click "Add a site..."
3. Enter your website address in the box that appears (e.g. www.canadaone.com) and click Continue.
4. You will now be taken to a screen that lets you add a title for your website and select one of two verification methods. You may need the help of your webmaster with this next step, as you will need to either add a page to your website or add a unique meta tag to your homepage. In both cases the page or tag are supplied by Google.
5. The final step is click the verify button. (If you opted to verify by uploading a single page you can check a test link before doing the verification.)

Once you have done this, as long as you are logged in using the same address you used for your Webmaster Tools account you should be able to post a comment as the site owner simply by clicking a checkbox at the top of the sidebar.

Can I block Google Sidewiki?

The first answer is yes, but are you sure you want to? While there are many reasons a site might blocks Sidewiki, doing so may send the impression that you have something to hide.

With that being said, it didn't take long for clever programmers to start identifying javascript and coding tricks that would effectively block Sidewiki comments. For example, a few people have suggested generating a unique, randomly generated page address that changes every time the page loads. In effect, this means that comments are left behind, attached to a page address that is no longer being used.

However there is an even simpler option. Google has said that Sidewiki currently does not work on secure (SSL) pages. So you can effectively block Sidewiki by changing your standard 'http://' pages to secure 'https://'.

One possible advantage of using SSL instead of a complex javascript solution is that it is less likely to have a negative impact on the search optimization of your site. This is uncharted territory, so you can expect to see new ideas as well as information about what does and does not work being released in the coming months.