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 you flood a Reddit community with posts or comments, you may be considered a spammer. Instead, post one or two times and see what happens.
If other users in a community historically downvote your posts or ones similar to yours, but you feel the need to continue submitting them anyway, you may be considered a spammer.