The first rule of promoting your own work in answers is to first, answer the question. If, links or references to other stuff aside, the answer is incomplete or unhelpful, it shouldn't be posted - and if it appears to be just a thin excuse to promote your own work or send folks elsewhere, then it's spam.
The second rule: be clear about your connection to things you link to. If you wrote it, say so. If you host it, say that. If your wife's brother plays golf with the guy who wrote it, you probably don't need to say that - but if that's the reason you're posting it, you might want to re-think that.
And of course, don't ever just use the site as a way to promote something, even if you're diligent about following all the rules while doing so. This just looks shady.
The FAQ spells all of this out pretty clearly.