There are huge difference in measuring transactional website and non-transactional site. Transactional website involves hard dollar signs attached to the web metrics. The conversions are pretty straight forward since you can directly link revenues or number of items sold to web metrics to make actionable decisions. However, in non-transactional website, there are many challenges in defining what is good visitors behavior.
When website owners are looking for methods to demonstrate value from their online marketing investments, it is important to be clear about the objectives. Non-transactional Web sites are generally harder to measure. The debates on development of new metrics and strategies for measuring concepts like engagement and user behaviors are huge challenge in web analytics world.
That is why you need a clear website objective that allows you to build context so each web metrics are meaningful, and actionable.
Once the objective is clear, you are able to clearly apply various metrics such as number of downloads, page views on specific page, number of registered users, etc. However, until you benchmark these metrics to your definition of success, it is hard to determine if those typical visitor behaviors were good behavior.
In transactional websites, website owners can clearly measure the ROI based on profits, costs per visitors, target earnings, etc. In non-transactional sites, defining meaning between the KPI (key performance indicators) to website objectives is the key to the success of web analytics.