When you're running a business (and yes, you're running a business if you're self-employed) it's important to know who you're selling to.
You may even have a few different audiences.
And you definitely want to be sending your existing customers different messages to possible customers and leads.
Identifying and separating these audiences is called market segmentation.
So, here's some thoughts from the Smashing Self-Employment Podcast on why breaking down your marketing into target audiences is important: