TargetingProfile and Relevance question

Are personas used at all in the rendering of content for end users or is it just the TagetingData collected?
Does the TargetingProfile object contain the persona information and if so, is it used to make a rendering decision
Also, what is the difference between a segment and a persona?

A persona is a concrete incarnation of a segment, used to preview a channel.
This and more at our documentation site, please start at

Cheers Jeroen