Servers are able to compile every request for a web page, arming its operator with the information needed to determine how popular the site is and which pages receive the most attention. When a web server processes a file request, it makes an entry in what is known as the “server log” on the server's hard drive. The log gathers entries across posterity, forming a valuable database of information that the site owner can analyze to better understand the website's visitor activity.
Not only can you see accurate measures of a site’s monthly search traffic, but you can see detailed breakdowns of where that traffic is coming from and what kinds of keywords are bringing the traffic. You can also see backlink information, such as which other sites are linking to the site, how often they’re linking, and how that data changes over time.
Note: There are literally dozens of places you can use a keyphrase, from captions to comments, web addresses to “Alt” tags. Feel free to get tricky if you’d like. But generally, the less visible it is to readers, the less important it is to Google. So focus on those elements listed above. That’s what readers (and therefore Google) really care about.
Web analytics is the measurement of the behavior of visitors to a website. In a commercial context, it especially refers to the measurement of which aspects of the website work towards the business objectives of Internet marketing initiatives; for example, which landing pages encourage people to make a purchase. Notable vendors of web analytics software and services include Google Analytics, IBM Digital Analytics (formerly Coremetrics) and Adobe Omniture.