Here's my simple answer:
You don't have to do any of that. The only thing you have to do, if you want to make a profession of writing?
Write a kick-ass book.
But, of course, we've all heard that, and even if we know that all we have to do is write a kick-ass book, there's also the fact that we hear about the author who turned mediocre sales into best-seller-status through an online promotion, the self-publisher who went trade because of a Twitter campaign, the blogger who got a book deal because she had 10,000 followers on Google Friends.
And even if we know that the most important thing is the book, we also know that we can probably help with online marketing. The thing is--unless you're rude, pompous, or otherwise unseemly, online marketing can probably only help and more than likely won't hurt. There are exceptions, of course, but I would think being a decent human being (or at least portraying yourself as one online) is really the safe zone to be in.
So, let's say you're a decent human being who has a book (or is working on one) and has decided that, while you know that writing the book is the most important thing, you also feel the need (or want) to do online promotion, social networking, whatever.
Recently, I was chatting with the Elevensies and the Tenners dropped by. Leah Cypress, author of MISTWOOD, had this advice for us:
“The thing about promotion: all of it MAY help. But nothing helps enough that it’s worth doing if you hate it.”
So: if you are convinced that you HAVE to market yourself, my best advice is to echo Leah--do only what you want to do.
I blog because I like to blog. Not to sell you a book. If you happen to buy a book, GREAT. But I'd blog anyway. I think my three years of archives before I sold my book should be evidence of that. I tweet because I like to tweet. I think it's fun. I've found out lots of cool information from links, met a few new friends, and love the drop-in-drop-out ability of Twitter. I use to sometimes advertise contests and such, but I try not to be a commercial because I'd much rather be a part of the conversation. I Facebook...sometimes. It's not my favorite. I have a page for people who like to Facebook so they can find info easily, but I'm honestly not on Facebook much (btw, the ACROSS THE UNIVERSE page on Facebook is run by my publisher, not me).
Do what you want to do.
And if you don't want to do any of it?
That's totally OK.
Have you seen Suzanne Collin's blog? No, you haven't. Because she doesn't blog. Neither do a lot of writers. Twitter's even more bereft of literary figures. For every Maureen Johnson, Neil Gaiman, and Meg Cabot who's tweeting and blogging, there's a hundred other writers who simply don't.
Are there advantages? Absolutely. I know of two writers who attribute their publication success to their blogs--although I think it's debatable. In my own personal experience, there are four books on my shelves that I bought solely because I "knew" the author online--I liked their blogs, so I sought out their books. But guys? I have hundreds of books. And only four purchases made based on an author's online presence.
So, while there MAY be a help to an online presence, don't forget what Leah says: "Nothing helps enough that it's worth doing if you hate it." If you enjoy it, by all means--go for it. But if you hate it? It's not worth putting up with.