There are many forms of advertising, but one that is often used (even without people realising they are doing it) is self-promotion. There are very mixed feelings on self-promotion. Some people feel that it is annoying and gives the impression that you feel you are an expert on a particular area, when this may not be the case.
Many people are using social media to self-promote their business but this doesn’t have to be a bad thing. If you hand out business cards, talk at network events or write and distribute articles about how you and your business can help others, these are all types of self-promotion and often a method of advertising that works well.
If you are confident in what you do, then why not promote that to others, after all the whole idea of advertising is to create new business. DJ’s for example, do a lot of self-promoting as when they are playing to a crowd they are effectively promoting.