Google's just-announced, despite its name indicating a focus on collaborative capabilities or a lightweight Web editing tool, is essentially a collection of customization tools for the Google search engine. Features include the capability to comment on search results, view other user comments, rearrange the search results, delete results to prevent them from appearing in similar searches, and have desired-but-missing URLs appear when conducting similar searches. With the exception of added comments, none of your actions will be seen by others or affect their search results. Even your comments won't be visible unless others explicitly activate the user comments for a particular search result.
These features at first sounded relatively useful and interesting (could there be a Google Reality Distortion Field?), but I slowly became confused by them and unconvinced that they would improve my search experience. Google's big win is that they've made results smart without you having to do anything beyond enter search terms and click links. Conceptually, these new features muddle that simplicity without adding any major benefit.
Typically when you're searching you don't know where to go or even necessarily what you're looking for - that's why you're searching and not simply navigating to the desired site. Rearranging, adding, and deleting results seem counterintuitive to that basic principle - these actions imply familiarity with the material. Granted, sometimes you've searched for something and want to get back to it, but typically the desire to return to the information is coupled with a previous lack of foresight that you would want to do so. Otherwise, why not just bookmark the page?
In particular, adding URLs and rearranging results seem incompatible with the essential function of a search engine. If you already know the address of the Web site you'd like to visit, why not just bookmark it rather than add it to your Google results page? The same issue exists with rearranging results; if there are a few sites that you consistently want to see at the top of a results page, why not just bookmark them and cut out the middleman?
Comment features make sense in some places, such as product reviews. The cost of purchasing and evaluating a product by yourself is high compared to the cost of reading other users' opinions. But when evaluating a Web page, the cost of doing the work yourself is much lower, and it would be far easier and faster to go to a Web page yourself than to read 20 reviews on it - especially when you have to explicitly activate those comments to see them. Additionally, you may find yourself sifting through comments made by trolls, bots, boosters, whackjobs, or simply people who seem way off the mark.
Given these problems, I've yet to see how SearchWiki could be attractive to a widespread population, though there may exist a niche market for this kind of search engine interaction. While it's always valuable to rethink and retool established ideas and methods, this particular attempt seems to fall short of bringing real change and innovation to the search engine. I think it's likely Google will simply use the data generated from this experiment to further refine their search algorithms than to seek to make SearchWiki a widespread release. For the moment, though, SearchWiki is merely a curiosity.
You may not see these features in your Google search results yet, since Google has enabled SearchWiki for only a subset of the massive Google user base. Plus, it may not last. Google's says, "This is an experimental feature served to a random selection of participants and may be available for only a few weeks."