When writing for a general audience, the writer should keep in mind that a general audience most likely

•knows little about the topic

•knows a lot about the topic

•is interested in the situation

•has the power to effect change

Knows little. 2 and 3 are both presuming too much, as it's the writer's duty to get them interested and informed. 4 basically doesn't matter, and furthermore may not even apply in many forms of writing. 1 is the best answer, as writing for general audiences is intended to inform and expand the horizons of the reader.