While creative, funny or "epic" adverts might be memorable in and of themselves, they are not always the most effective marketing tools because the packaging overwhelms the message contained within, according to one expert.

Herndon Hasty told Search Engine Watch that truly effective ads in any channel from billboards to pay per click marketing are the ones that sell products, promote brands or encourage a particular decision.

Calls to action are therefore crucial to successful search engine marketing, no matter how simple they may be, he added.

In paid search ads, calls to action such as "shop" or "browse" should be included in the headline or description to give direction to the audience.

They should also be included in landing pages, where they could take the "more forceful" form of an add to cart button.

"Getting your potential customers’ attention is important, but getting them to direct that attention to doing what you want them to do is an absolute," Mr Hasty said.

According to recent research by Outsell, spending on digital marketing in the US is set to overtake print budgets for the first time this year, hitting $119.6 billion (£78.1 billion).

News brought to you by ClickThrough – specialists in Search Engine Optimisation and Internet Marketing.