Cut and Paste, from another web site.
Alexa is a free, ad-based product which installs itself into your Internet Explorer or Netscape browser. It ads a bar which has a series of links into your browser which gives quite a bit of information about each web page that you visit. For example, the contact information, related links, reviews of the site, traffic and some other information is displayed.
Sorry for the caps, but ...
Alexa has an additional purpose, however, as is explained in their privacy policy.
"ALEXA COLLECTS AND STORES INFORMATION ABOUT THE WEB PAGES YOU VIEW, THE DATA YOU ENTER IN ONLINE FORMS AND SEARCH FIELDS WHILE USING THE ALEXA SOFTWARE, AND, WITH VERSIONS 5.0 AND HIGHER OF THE BROWSER COMPANION SOFTWARE, THE PRODUCTS YOU PURCHASE ONLINE. ALTHOUGH ALEXA DOES NOT ATTEMPT TO ANALYZE WEB USAGE DATA TO DETERMINE THE IDENTITY OF ANY ALEXA USER, SOME INFORMATION COLLECTED BY THE SOFTWARE IS PERSONALLY IDENTIFIABLE. ALEXA AGGREGATES AND ANALYZES THE INFORMATION IT COLLECTS TO IMPROVE ITS SERVICE AND TO PREPARE REPORTS ABOUT AGGREGATE WEB USAGE AND SHOPPING HABITS."
So what does this and the remainder of a very long privacy policy translate to in plain English? Alexa watches you surf the internet and transmits the URLs of the sites that you visit back to their computer system. Their stated intention is to build up a list of related links for each page that you visit. They also watch your shopping patterns to get an idea of what you are purchasing online, and presumably where you are purchasing things on the internet.
It's very interesting that Alexa is owned by Amazon.Com, and one of the "great" features of their browser bar is something they call a "shopping feature". This allows Amazon (and other business partners) to offer you comparative shopping advice while you surf through other sites.
Alexa now has a well written and lengthy privacy policy, but it was not always that way. In fact, there is a pending (as of May) class action lawsuit because Alexa didn't have a privacy policy posted on it's website at all. This meant that people who downloaded and installed the bar were not made aware that their movements through the internet were being watched and recorded.
I view this product as a major threat to privacy. My advice to anyone would be to do without it - the product is not that useful. It is most definitely spyware, although now that Alexa has taken the time to write up a privacy policy at least we are a little more informed as to what they are recording and what they are attempting to accomplish.