Slicecast

Snapshot is a nice addition to the just launched Search Engine Compete, operating in a very similar vein to Alexa - ie collecting user data and aggregating against an overall population.

NOTE: This entry applies to the US only 

Compete says that its data is superior to Alexa's, because it uses more than just a toolbar to collect it. Compete gets its data in the following ways:

• The Compete toolbar - works very similar to Alexa toolbar, in that "community members" download the toolbar and opt in to share information on the web pages they visit, as well as other marketing data.
• ISP's
• Opt-In Panels
• Application Providers

So, at first glance it appears that the validity of the data is more worthy than Alexa. Compete currently reports more than two million members - and since the site has only just gone out of Beta we can expect this number to increase substantially, as well as when it increases vendor relationships to increase the validity of the data. This is important because currently only highly trafficked sites feature well (same problem as Alexa, but managed differently) because of the process of aggregation of data - data weightings will be applied for the aggregation meaning that if my blog gets three visitors a month, all of whom install the toolbar - then my site will appear to be highly popular. Compete should resolve this with use of third party data.

As with Alexa, there is ranking, pages/visit, avg stay and comparisons (up to 3 domains in total). There's also a People metric - an estimate of unique visitors to a site; an interesting metric.

Where this tool will be useful is in side-by-side analysis of your site versus your competitors site - hopefully the granularity should allow visual comparisons to be made. It's unlikely you'd want to use this data beyond such comparisons, but as a market research tool supporting your own analytics tool it should be a useful addition to your arsenal of tools.