For me, this is not about following an authority in a topic. It's based on the observation that *the best writers are so interesting that you want to read whatever they write, no matter what the topic.* (Like when I was in college, I would sign up for classes by the best professors no matter the subject.)
Also, there is cross-pollination between people and topics. Interesting topics surface new people for me to follow, and interesting people introduce me to new topics to follow. Much easier to discover and expand my follows if there are both options, working across each other.
Here's my product suggestion, as a fellow techie with some product and engineering background, and as a fairly avid user of social networks:
* Let me follow both people and topics, like on Quora. I see content in my feed if it's by a person I follow, *or* on a topic I follow.
* Make it a one-way follow, like on Twitter/Quora, not a two-way “friending” action, like on Facebook.
* As you build the community, set expectations that you should follow people based on enjoying what they write, *not* based on pre-existing social relationships like friends, family or co-workers. (A one-way follow model helps with this.)
* Let me also mute people and topics. Muting overrides following, so if there's content on a topic I follow, but by a person I've muted (or vice versa), then I don't see it.
* The above should cover 99% of use cases. If that's not enough, then someday, for power users, let me follow or mute specific (person x topic) combinations. My guess is, you will simply never need this feature.
PS: I sent @yaypie more thoughts on this in email a little while ago.