Online video sites have surpassed email providers and sports sites in the UK, with Internet users spending 240 million hours every month watching online video content, according to Web analysis company Experian Hitwise.

Experian Hitwise said in its new report, "Online Video: Bringing Social Media to Life", that online video websites saw a 36% year-on-year jump in September 2011, when the UK Internet population made over 785 million visits.

YouTube was the clear leader with 70% of all visits to online video sites. UK Internet users spend 184 million hours watching YouTube content, with an average session time of 20 minutes.The Google-owned site is also the third most popular website in the UK after Google UK and Facebook.

The video-on-demand (VOD) services from BBC iPlayer ranked second, while ITV Player was at the third spot. Niche sites have also seen a huge increase in traffic, including videozer (+853%), MSN Video (+913%) and Hulu (+123%), revealed Experian Hitwise.

Experian Hitwise marketing research analyst James Murray said the popularity of video websites represents a huge opportunity to the online marketer.

Murray said, "The average Internet user will make 18 visits to video sites a month and almost half will visit at least three different sites. While YouTube dominates the market, the increase in traffic to video-on-demand and more niche sites demonstrates that content is what matters most to today’s Internet users and they’ll go to whatever site has the content they’re most interested in viewing".

The top topics that drove traffic to online video sites are music, TV, films and gaming, but music is the biggest driver of traffic, accounting for 33% of search clicks, said the report. The majority were looking for music videos, where Lady Gaga was the most searched for artist, said Experian Hitwise.

Among the TV search clicks, 17% were for TV-related search terms; specifically EastEnders, Britain’s Got Talent, X-Factor and South Park, while gamers were looking for trailers for new games and walkthrough cheats.

Murray said that brand marketers should make online video an important part of their digital startegy.

He said, "Online video is a very diverse media that can be used to build brand awareness, to bring traffic to a website, as an educational tool to demonstrate a product or service, as a customer service channel, or as a way to attract a completely new online audience".

Murray also cited Domino’s and British Airways as good examples of how brands can use YouTube as a customer service channel.

"Others, such as Yeo Valley, have created successful multi-channel advertising campaigns by repurposing TV adverts online, where the online advert had a potent effect in generating media awareness and enabled the company to reach a completely new audience," said Murray.