I don't think so, the sophomore in COMP 101 isn't that valuable to SO because they add no knowledge to the ecosystem, they'll come from Google, read the answer and leave. But the expert Java dev with 15 years of experience who posts on Usenet forums is someone who may have very specific preferences and will entrench themselves in a platform.
I'd assume these news also apply to the properties on stackexchange that have a lot of non-tech content. As for the rest they probably want them to create accounts, that'd be one way to do it.
Wouldn't that be SO's target market?