BMW should really stick to engineering cars, rather than web pages. On Monday, the automotive firm was booted into touch by the internet’s motherlode - aka Google - after trying to artificially inflate its rankings.

Why did this happen? Will Google’s quality control enforcers come knocking on your door?

Website owners need not panic. BMW got it badly wrong in Google's eyes, that’s all. But there are some lessons to learn from its misguided search engine strategy.

The problem? BMW had a "doorway" page, essentially a page that appears just before the BMW homepage. In the eyes of Google, doorway pages are evil, unnecessary and generally used to artificially inflate search rankings. As a rule, this tends to be true.

In BMW’s case, it only showed the doorway page to the search engine robots. If you or I visited the BMW website it would instantly redirect to the main BMW homepage. Clever, right? Actually no: by trying to bait the search robots it has been found out. Not so clever.

But even more disliked than the doorway page was the amount of blatant keyword spamming for terms like "BMW Neuwagen", which translates as "new BMW". The BMW doorway page was littered with them. Bad form. This sort of thing still works to some degree on MSN, but Google looks at keyword/keyphrase density and anything over the top will be red-flagged.

Where did BMW go wrong? Well, any reputable search engine marketing agency will tell you that doorway pages and keyword spamming are unethical and should be avoided. And perhaps that’s the issue: the search marketing industry is still riddled with so-called "experts" peddling shoddy advice. There are plenty of great agencies out there, but clients need to be clued up before going through the process of agency selection.

What constitutes shoddy advice? Well, part of the trouble is the speed of change, as search engines must continually tweak their algorithms (the formulae used to sift the internet's content) to deliver the most relevant results. Good practice for Google in 2002, for example, might be considered bad - or useless - practice today. Agencies and experts must be bang up to date.

If you do outsource your search marketing requirements then you need to choose an ethical agency that knows the difference between right and wrong. Agencies and consultants charge an average day rate of about £650 in the UK, or you can optimise your own website in-house.

The first rule in selecting a search agency is to avoid anybody who says they’ll "secure a No1 Google listing, guaranteed, or your money back". That just opens the door to bad practice (especially when a fee is riding on it). Temporary measures are not the solution.

The second rule is to point and laugh at anybody that talks about search engine optimisation (SEO) as some kind of "black art". It isn’t remotely voodoo, but is about hard work, about putting the basics in place, and about avoiding unethical activity. No hidden tricks.

So what then, are the fundamental rights and wrongs of search marketing? First, determine your keyword goals. What search terms do you want to rank well on? BMW wanted to be highly visible for "New BMW", but how could it have optimised its website ethically?

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