All tokens in an ICO need to have a purpose and a function, and there are a number of models and definitions available discussing the various characteristics of tokens.
To help us to understand tokens, we can consider the money in our wallets. People work and produce goods or services, thus producing economic value. This value is exchanged for money and then the money can be spent on needs and wants, sometimes not necessarily in that order. The government controls the money supply and changes various aspects of it based on monetary and fiscal policies. The money we earn is spent within a country and if we want to spend overseas, we need to exchange it. This then creates the economy that we all participate in.
Let's now look at ICO projects where we have tokens. People work and produce value in exchange for tokens. The work can be in the form of producing content, such as blogs or videos, or the user giving their attention to an advertisement. The tokens can only be spent...