It is fun to record your travels by bike. In part, it is just to remember where you went and what you liked about it. On the the other hand, if you are on a very long tour, cross canada say, or even cross russia, a lot of people will be interested in how you are doing and will want to know that every thing is going well. It is a good idea to update your location and other information as you go along just to keep them informed.
There is lots of software available to help you do this. Following other peoples blogs is one way to learn about this. These blogs vary.