"Zipper Interactive, a 1st party Sony developer best known as the creators of SOCOM, have posted new job listings on their website, looking for a senior server engineer and a senior network engineer. Under both listings, they have listed "Experience with persistent MMP server programming a plus". In addition to that, 2 years ago, they also had a job listing looking for someone with experience in "large scale online games".
With Slant Six Games producing the fourth entry in the SOCOM series instead of Zipper, this raises questions as to what their next project could be. Could Zipper's next project be some sort of MMO game? Certainly seems that way. Expect some new information from Sony at the upcoming E3."