Ever wished you could leave a comment about a website that had no commenting system? Well, thanks to Google’s latest product, now you can.

Google announced a new addition to its popular Google Toolbar today, Google Sidewiki.  Any browser that can run the Google Toolbar will now be able to have a pop out window on the side that you can open up and see what other people are saying about it.  You can also add your own thoughts, or if no one has started a Sidewiki for it yet, you can.

While Google is promoting this as a way for Web surfers to help one another and to get more information, this also seems like it could be ripe for abuse.  Imagine a business getting a ton of slanderous Sidewiki comments.  True or not, it could ruin its reputation and they have no control over it.

It also could be seen as a bad thing by blog owners because people might start using it more than the comment system built into the site.

While it’s an interesting idea, the possible abuses are rather frightening.  It will be interesting to see how this shakes out.  Here is a video explaining a bit more about what it does.

People who already have the Google Toolbar installed can expect to see the buttons show up shortly, but if you can’t wait, you can go download a new copy here to get the service immediately.