This is a trick question, of course. It's never an either-or prospect. Of course we writers should go out and take the opportunity to meet other writers in person. Of course we should seek out agents and editors and introduce ourselves. But we can't ever forget about the writing. It's the writing that makes us writers.
This issue is at the top of my mind because I've been in a place for the last little while where I haven't had time to write. That while will soon be ending, fortunately. Janice Hardy this morning told me that I shouldn't feel bad because I have been very productive, just not productive in the writing part of my life.
I think I'm at peace with it at this point. However, I'm the kind of writer who feels a sense of loss if she can't write. If this were not the case, I don't think I would have chosen to be a writer, but the Muse is usually rather demanding for me. In a few days I'll be sitting down beside her, shaking her shoulder and saying, "I'm back. You can wake up again - sorry about that."
There are two parts to a writer's professional identity. For this post, I'll call them "Face" and "Voice."
My trip to WorldCon last week was all about "face." Of course, it was also about raising my spirits, getting me to feel connected to the community, and all of that. But I was achieving that by enacting my face as a writer. I don't see this as something controlled or disingenuous. I'm calling it "face" from an anthropologist's point of view, which is to say that this is something we do with limited conscious control, just by being ourselves. When I meet writers and get to know them, I want to know what they look like, and what they sound like, and what they are interested in talking about, and what they are working on, and how they think about what they are working on. All of this together - the verbal and social aspects of the writer - are the "face."
When you're working with face, however, you get very little sense of "Voice." Your voice as a writer is your work. It's not what you say about your writing, but the writing itself. When I was at WorldCon I kept saying to myself, "Wow, after this I have to go home and write some awesome stuff, just so I can continue to deserve these fabulous people." The writing is the part of you that endures. It's the part of you that people experience when you're not standing in front of them. Because of what a writer does, it's as much "you" as your face - and in fact, it's more you than your face most of the time.
Both of these sides are worth working on.
You should go to conventions and be on panels and meet people. It's very important. But you should never stop writing completely, because if you stop writing, you're not a writer. I'm not talking about those crazy hiatuses due to life and stress and everything. I mean, don't ever shake your Muse's hand and say "it didn't work out" if you want to be a writer.
Similarly, your voice is indispensable to your writer's identity, but it doesn't have that many chances to speak. It depends on the generosity of an editor who sees you story and can be inspired. Thus, it's critical for you to use your face to help create your public identity as a writer.
Okay, so at this point I ask, "Where does the writer's online presence fit in?"
I see it as somewhere in between the face and the voice. It's not really your "face" unless you're actively on a Google Plus hangout somewhere. But it's not really your voice unless it's actually your fiction. It's a go-between environment, where both face and voice can be maintained, with limitations. Your blog about yourself can establish an identity for you and contribute to face; your blog about writing can hint to readers about your writing style and contribute to voice. It all depends on what you do with it. A hangout can contribute a little to face and allow you to represent yourself as someone who writes (and help your productivity, in the case of writing hangouts). Online fiction contributes to your voice but may not reach as many people as you hoped if you're posting it yourself without pay. An online identity must be constantly and consistently maintained and grows only very slowly - but it's worth doing if you can make it work within the constraints of your life, because it can help bind face and voice together and strengthen both.
It's something to think about.