Twitter generates nearly 10 percent of social media global hits to websites, according to new research from StatCounter.

The report found that Facebook is still the main source of traffic to global websites with almost half (48%) of social media hits followed by StumbleUpon with 25 percent.

The data for March is based on 13 billion page views across the StatCounter network of member sites. The analytics firm just recently added social media to the categories its tracks.

 "From a business perspective the findings suggest that there is merit in having a corporate Facebook page or Twitter account," said Aodhan Cullen, CEO, StatCounter.

"The surprise packet is StumbleUpon, which over the past year has been consistently in the top two Social Media sites in terms of generating global website traffic. Indeed, in the US in March StumbleUpon was number one ahead of Facebook in terms of website traffic generation."

The top social media sites to generate global website traffic after Facebook, StumbleUpon and Twitter are YouTube (6%), reddit (4%), Digg (2%) and MySpace (2%).

"Social Media market share fluctuates a lot more than browser or search statistics," said Cullen.

"For example, Facebook peaked over Christmas and the New Year with almost three quarters of the total, perhaps reflecting its important role in communications between families and friends."