Is your writing a hobby or a business?

After receiving some very interesting emails on my post asking readers how they would spend $5000 for book marketing, it made me want to delve into the subject further. Most of the responses were "Are you crazy, why would you spend $5000 on marketing an indie book?" I counted 24 emails literally giving me a virtual thumping on the head for being so foolish. But, it made me more confused. Is this a business or is it a hobby? One reader said that $5000 doesn't come close to competing with the big publishing companies therefore it would be throwing money out of the window because it still wouldn't drum up enough business. And another reader suggested not to be concerned with paid advertising but on building 1000 readers and letting it grow slowly. So, are they right? How do we know? I have a theory that we as indie writers have been so conditioned that our books are not going to sell that it stops us from trying from the moment we write The End on the last page of our books. If we don't try to sell our books commercially doesn't that just make what we're doing a hobby? It would be the same as opening a business in the middle of the desert hoping customers will show up or hoping one customer is going to go back an tell enough people to keep your desert store open. How are we to reach readers if we aren't supposed to spend money promoting it? Okay, there's word of mouth, but word of mouth isn't free, I have proof of that from the number of freebies I've sent out to bloggers, reviewers and winners. Don't get me wrong, I'm not itching to spend $5000, I can think of a lot of other things I'd rather spend $5k on, like European vacation or a pair of beautiful diamond earrings. But I don't want my writing to be nothing more than a hobby, if that was the case then most of us would be satisfied with writing for the simple pleasure of it with no real intentions of success. I don't know if that's enough for me. Am I alone? So,is your writing a hobby or a business? I'm just asking.