Okay, I am completely lost here. Um... (tries to form semi-intelligent questions)
Why are meta-tags okay, but "hidden" keywords aren't, when your customers are unaware of either thing when they visit? What's the difference? What is "flooding" or "stuffing" search engines? What are "illegal"
SEO techniques? Do you mean literally against the law or against SE policies? And how can anyone be expected to know what the policies are for every search engine on the planet and whether you're violating any of them?
Help???