What are the best tools to analyze a competitor's website?

Besides cookies, what tools do website analysts use to track people's behavior?

• Reading GigaOM's Privacy Policy, I was struck by this section: "In addition, GigaOM uses third party analytics providers and products to obtain, compile and analyze Information...These analytics providers may use tracking techniques other than HTTP cookies to recognize your computer or device and/or to collect or compile this information. These techniques may be used directly on GigaOM. GigaOM has no responsibility for the technologies, tools or practices of the third parties that providing analytics products and services to GigaOM. Please also keep in mind that your web browser may not permit you to block the use of these techniques, and that browser settings that block conventional cookies may have no effect on such techniques." What are these "tracking techniques" GigaOM is referring to?

• Answer:

  There are a variety of techniques. Flash allows pages to store persistent data, along with the new HTML5 data store. Also, there are very subtle tricks, such as storing a tiny image in your browser cache, which contains data stored in RGB values. It’s all very evil. Most of these techniques have been gathered together into the Evercookie library, so you too can be evil with minimal effort. http://samy.pl/evercookie/ Also, there are the fingerprinting techniques. See Panopticlick: https://panopticlick.eff.org/