Search Engine Optimisation (SEO) has taken off in business - practitioners basically tweak a website so that it appears higher up the search engine's listings.

However, businesses are being warned to be careful when carrying out SEO techniques - or they could be blacklisted by the very search engines they are trying to impress.

That's what happened to The Search Company when it employed a SEO to boost its rankings. It turned out the tweaks were breaking Google's guidelines and the search engine banned its website, the Daily Telegraph reported.

Check out Google's guidelines here.