Ethical SEO, I hear you say, what is it and is there such things as unethical SEO???  Well, like pretty much everything to do with our business, social, and home life, SEO has ethical and unethical techniques.  While most search engine optimisation companies do walk the straight an narrow, keeping inside the realms of ethical or "white hat" SEO, some companies do take advantage of some devious tactics to promote either their own sites or their clients sites.

Keeping within the boundries of ethical SEO is quite easy (and the majority of the time quite blatantly obvious), if you are not trying to mislead or spam the search engines, than more often than not your SEO tactics will be considered ethical.  It is when you reach the fork in the road, and decide to take a stroll down the dark path of unethical SEO and try to decieve not only the end user but the search engines themselves that you have strayed into the dangerous and immoral world of black hat SEO.

While there are many ethical techniques to get your website ranked highly in the search engines, some people will always look for a quick fix, usually without thinking or knowing of the possible consequences.  The black hat techniques vary, but usually all involve "hiding" things (usually keywords and links) from the search engines. 

In 2006 BMW Germany was blacklisted for using black hat SEO tactics and consequently was removed from the Google index, so if you think that you can get away with using devious techniques please stop and think "If BMW couldn't get away with, how can I?".

A while ago an Australian search optimisation company was found to be using devious tactics by offering free hit counters for websites with hidden links contained within the code. Sneaky sneaky, but although it did give them a bit of a boost in the SERP's, eventually they where caught by Google and are now facing a long, hard struggle back up the ranks.

So, it's pretty easy to figure out whether or not you or your SEO company are using any black hat tactics, ask "Does that sound ethical?" and if it dosen't, change your SEO techniques quick smart, before the wrath of Google falls onto your site.

I also found this great little video on YouTube giving a quick rundown on the subject.  Happy Viewing :).