By using "unethical" search engine optimisation (SEO) techniques, online marketers can end up doing more harm for their campaigns than good, it has been suggested.

Writing on Search Engine Guide, Susan Esparza claimed that those who constantly send out spam could find themselves fined or even banned from search engine rankings.

She said: "When infractions are serious, it can take many months to convince the search engine that you corrected the problem and deserve a second chance."

Ms Esparza warned against webmasters placing identical content across a number of websites and then integrating a number of links between them for the sole intention of attempting to boost SEO.

"Search engines suppress duplicate content because it holds no value for their users," she said.

Meanwhile, repeating the same keyword throughout meta tags and website copy was also discouraged.

She advised that advertisers should look to repeat a keyword no more than seven times per 200 words of text.

Using hidden links which are readable by search engine bots but not visible to the human eye was also highlighted as unethical and is likely to be considered spam.

Shaun Crowley, writing on Freelance UK earlier this year, claimed that 'well-executed link building' can be one of the best ways in which advertisers can increase their SEO status.