In this video Alexei covers the basics of 80/20 principle when it comes to digital marketing. The reality is that most businesses want to spread their entire marketing budget across their entire business. The downside of that is that none of the services will get full exposure unless the budget is huge resulting in a lack of exposure. If you would like to market your service or product properly, do it one thing at a time and track your results.
To learn more about 80/20 or pareto principle check out this Wikipedia article