Bumping should be done not for advertising purposes, but to inspire further discussion.
Bump your own threads very sparingly. You are allowed to do it, though, but don't do it over and over for the same post, please. Once, if that, is normally enough. Do not bump your own threads to express impatience.
You're free to bump other people's threads to inspire further discussion. Please don't make multiple accounts to abuse this rule. No matter how many accounts you have, you're still the same person.
If a large percentage of your posts are bumps, you're doing it wrong.