You left the exact same comment on the Bluetoque Marketing post on Sidewiki mentioned above. l wrote that article too. :)
For the benefit of the readers here, I will summarize what my response was on the Bluetoque site, and tailor it more toward the content of the 40tech article, which is more about a user approach to Sidewiki as opposed to a website owner:
Essentially, I believe that as a business owner, your concerns are valid. There are, as I mentioned in the article, definite reasons to be concerned about Sidewiki, especially if it takes off and Google’s new algorithm is less than up to the task it is supposed to be. No one here is jumping up and down for joy and trying to be a Sidewiki evangelist at this point. It should be recognised, however that Sidewiki is being presented to the world as a useful service and that some significant time and effort has gone in to trying to make it so.
The simple fact is that the idea of web annotation has been around for a long while and will likely remain so even after Sidewiki is a forgotten wisp on the wings of memory (yes that is what I said: forgotten wisp, wings of memory :P) . It is best to understand that reality, and a smart decision for business owners to put some energy into mitigating the potential damage that might come from widespread use of the service. I cover ways to do just that on the Bluetoque Marketing post (linked in the article above).
As a user, I find the concept of Sidewiki intriguing and potentially useful if the inherent spam problem is dealt with effectively. As a business and website owner, I am a bit trepidatious about it as the comments are always floating there, right next to my webpages — and that could prove to be problematic in the public relations department. However, businesses can find similar issues with Twitter, Facebook, Friendfeed, or any number of frequently used, real time or delayed time web services, including blogs. As long as the services or articles are are indexed into search results, users will find that information and will try to make an informed decision. As they should.
I do think that you had an extremely important idea in your post to google, though: It would be fantastic if there were a service like Google Alerts that allowed website owners to be notified when someone posts a comment (or a comment that contains certain keywords) on the Sidewiki associated to their website. It would be only fair, I think, and would go a long way to giving business owners a fighting chance to deal with any fallout from Sidewiki.
Once again, thanks for your comment, and please feel free to disagree and start a dialogue. We appreciate and encourage an intelligent exchange of ideas here! :D