PlayStation isn't the only handheld device to not offer support for Flash. Apple's iOS devices have received criticism, mostly at launch, about lack of Flash support. Many cite the believe that HTML 5 is the way of the future, but according to the magazine, Sony's official stance on Flash support, per their own FAQ, is that the company is "evaluating the opportunity to offer non-gaming applications/content and will announce details at a later time."
The report includes a few other unannounced details about the PS Vita, including news that you'll be able to transfer PSP save files to the Vita from your computer or PS3, that PSP games will run on the Vita with bilinear filtering, and that the system won't support original PlayStation 1 Classics at launch. Of course, that last report is in direct contradiction to SCEA's official statements. It is possible that Sony intends to patch in support at a later date.
Sony's PlayStation Vita releases on December 17th in Japan, and February 22nd in Europe and North America.