Jammer (vg) is the standard view of Jammer Core.
Initially it will function as a reskin of Ludum Dare (com). As things evolve, Jammer will become more Game Jam agnostic.
The goal of Ludum Dare (com) is to focus on the Ludum Dare event itself, where as the goal of Jammer (vg) is to be focused on the game jamming community. We still run Ludum Dare, so LD will certainly be highlighted on Jammer (vg), but as Game Jams and the community around them evolve, Jammer (vg) aims to cater to that.
Accounts are "Jammer Accounts", created through jammer.vg and ludumdare.com