What constitutes spam?
It's a gray area, but some rules of thumb:
It's not strictly forbidden to submit a link to a site that you own or otherwise benefit from in some way, but you should sort of consider yourself on thin ice. So please pay careful attention to the rest of these bullet points.
If your contribution to reddit consists mostly of submitting links to a site(s) that you own or otherwise benefit from in some way, and additionally if you do not participate in discussion, or reply to peoples questions, regardless of how many upvotes your submissions get, you are a spammer. If over 10% of your submissions and conversation are your own site/content/affiliate links, you're almost certainly a spammer.
If people historically downvote your links or ones similar to yours, and you feel the need to keep submitting them anyway, they're probably spam.
If people historically upvote your links or ones like them -- and we're talking about real people here, not sockpuppets or people you asked to go vote for you -- congratulations! It may not be spam! However, you still need to follow the guidelines for self promotion
If nobody's submitted a link like yours before, give it a shot. But don't flood the new queue; submit one or two times and see what happens.
To play it safe, write to the moderators of the community you'd like to submit to. They'll probably appreciate the advance notice. They might also set community-specific rules that supersede the ones above. And that's okay -- that's the whole point of letting people create their own reddit communities and define what's on topic and what's spam.
If you're thinking of doing any self-promotion on reddit, you might want to read this first.