The economic logic behind freemium is

“When the supply of a product increases, the demand for its complementary products also increases.”

the free product is the driver of the revenue creating products and more free users means more paying users.
Since additional distribution of a free product costs close to nothing, the success of a freemium business will increase with the number of people using it.

there are two main ways of helping this along

Actively promoting this

By actively promoting your product, you make sure that more people get to know about it – which will lead to more users.
the generous nature of freemium fits very well with the emerging field of social media, and social media marketing has proved to be a good way of promoting a freemium product.

Removing barriers for people to access it if it is hard to access your free product some people will stop before they get to it. Not only will these people not be exposed to your thoughts, they will also have wasted time on you.