Fuzzy Cognitive Map (FCM) is a qualitative modelling and behaviour simulation method that can utilize imprecise and incomplete information, like one found on the web, to model different systems. Knowledge mapping from such information to a FCM can be accomplished with documentary coding method. This paper shows how this can be done, presenting a FCM map that models internet spreading rate in different countries. Obtained map can simulate the system behaviour and can be used as a decision support tool. The quality of proposed approach, that uses documentary coding to build FCM models from imprecise and incomplete knowledge about system domain, is compared with multiple linear regression statistical method for building models for prediction and explanation. The conclusion made in the paper from the results obtained in the presented example is that when dealing with imprecise and incomplete information about system the FCM method gives robust system model.