Read this nice article on the 7 Web Analytics Sins from ClickTrack. The 7 sins are:
Sin #1: Simple Visitor Counts
Learn the factors that can potentially skew visitor data.
Sin #2: Search Term Popularity
Understand why marketers must concentrate on the quality of visitors a keyword delivers, rather than the quantity.
Sin #3: The Linear Funnel
Learn the reasons why traditional sales funnels can lead to dangerous assumptions.
Sin #4: Data Overload
Know why it’s important to be able to separate interesting information from actionable information.
Sin #5: Relying on Absolute Number
Understand the reason why it’s more important to concentrate on trends instead of absolute numbers.
Sin #6: Relying on Top 10 Lists
Learn how getting stuck in your top 10 referrers can cost you long tail opportunities.
Sin# 7: Technicolor Report
Understand the reason why the way that information is displayed can have a huge impact on ease of use and perception.
For more information visit ClickTracks White paper at http://www.clicktracks.com/downloads/7-web-analytics-sins.pdf