We can not fully understand our customer, but we can try to predict factors that influence his behaviour. The internet customer behaviour model is my interpretation of factors that influence a customer to do a (first) buy on a website

The model is based on a model for e-commerce (the tamcom model), where the sale is the main goal. It shows the 6 main barriers on the internet for customers, plus some detailed aspects per barrier, The details of each area make the task at hand, greating a great website, so complex. That is probably why so few complete studies have been done on this topic, and only partial studies are available.

The bigger picture

This model helps to define the online value proposition,  and show it's not the only factor for success. The model  shows main areas and elements that may need attention to be more successful. I believe that next to the user satisfaction of the product or service to be sold, trust, usability and Relevance are the most dificult factors to get right in the decisionprocess.
But before we even get there, availability, findability, and accessability must be provided for.

Using this model to define the goals for your website will probably give you a much better website from the start. understanding this model you will prioritize the most important values and barriers in the analysis and development process.

There may be more elements for specific target groups.

On the web use strategy
to be faster than the rest