Visto, a provider of secure push email for mobile professionals, has announced that it closed on more than $51 million in new financing. The financing round was led by Oak Investment Partners with new investor DFJ Growth Fund and existing investors including Draper Fisher Jurvetson, Meritech Capital Partners, DFJ ePlanet Ventures, Rustic Canyon Ventures, GKM, and Blueprint Ventures. Visto will use the funds to grow its subscriber base and to fuel global expansion while supporting its mobile technology. Visto has also announced that Barry Schuler, the former chairman and CEO of AOL, has joined its board of directors. He was a senior member of the management team at AOL.