A new study conducted by Greenlight, a digital marketing agency, suggests that Google+ could be more successful than had been previously expected and that Facebook, should it actually launch a search engine, would capture nearly a fourth of the global search market immediately upon launching it. Given this market share, a Facebook search engine would instantaneously barge through all non-Google search engines to secure the spot of second most-used search engine in the world (excepting China, Japan, and Russia).

The comScore ranking of search engine market shares for March 2012 show that Google claims 66.4%, Microsoft (which includes Bing) includes 15.3%, and Yahoo! has 13.8%. However, Greenlight’s survey, “Search & Social Survey (2011-2012),” which included responses from 500 people ranging from students to medical stuff to the unemployed, shows that a solid 5% would “definitely” use a Facebook search engine as an alternative to Google while another 12% said they’d probably use Facebook’s search engine. Facebook’s acquisition of a quarter of the search market would rely on its ability to convince those without any search engine loyalty, namely the 27% of respondents who replied “Maybe, but only if it was better than Google and Bing,” that its unique search engine is what they need. But even without proselytizing its search engine to the wandering internet user, Facebook would still probably amass 17% already, which would still push it into second place given you have to imagine every other search engine company’s numbers would go down a little bit – and that’s a worse-case scenario.

“These stats therefore suggest Facebook could capture around 22% of the global search market by simply launching its own search engine tomorrow morning (the ‘Definitely’, ‘Probably’, and half of the ‘Don’t know’ respondents combined),” said Greenlight CEO Andreas Pouros in a statement. “It wouldn’t need to be a spectacular engine either, just well integrated into the Facebook experience and generally competent.”

Greenlight projects that Facebook could increase its search market share to a maximum of 50%, but that dexterous feat would include some Asgardian levels of force and strategy.

And even if Facebook’s search engine was soaring through the market with the force of Ragnarok, it’s still going to have some staunch resistance from Google and what it’s been able to do with social search thus far. In the same Greenlight study, 23% of Google users said they’ve been using the +1 feature on search results, which the firm says may be more than what had been assumed initially.

Google’s +1’s still lag behind the 35% of people who Like a brand or company on Facebook, but Facebook’s had a healthy head-start on Google+ and, given Google+‘s relatively young state, most of the world’s top brands haven’t even launched a dedicated Google+ page for their companies.

Given that a Facebook search engine would likely be regarded as an instant success in the world of search, Google very well might need to begin worrying about the very real possibility that it’s going to have a juggernaut of a challenger sometime in the near future. It could be one reason why Google’s been tweaking its search algorithms so much lately.

Do you agree with Greenlight’s speculation that Facebook’s search engine would be an immediate challenge to Google’s search dominance? Would you be welcoming or hesitant of a Facebook search engine? Chime in below with your thoughts.