If you were to look at the definition of an ecosystem, you may find something along the lines of this:
An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can come in any size but usually encompass specific, limited spaces (although some scientists say that the entire planet is an ecosystem). Wikipedia.
This is the true definition of what an ecosystem looks like, and is very much based on the natural world.
However, when you look a little further into the definition shared above and beyond that, you can start to make a strong correlation between such an ecosystem, and the community around a blog or social presence.