In step with warnings that subscriptions for Star Wars: The Old Republic would decline (and likely in line with LawnGnome's prediction in the comments), BioWare and LucasArts will be conducting another Weekend Pass Free Trial in an attempt to get more players to try the game.
The Weekend Pass Free Trial has already begun and will run until Monday, April 23rd, 7:00AM GDT. Perhaps they're deliberately trying to tear people away from the Diablo III Open Beta?
No payment or credit card is required for the Free Trial. Any progress for trial characters can be saved, though capped at Level 15, and players will be able to explore the Origin Worlds of each character class and a faction's Capital World. You can join friends in Flashpoints and experience Player-vs-Player Warzones.
Those who purchase the game and active their account before April 22nd will receive the Legacy Tauntaun Ram Pet as a reward.
BioWare should also concentrate on fixing some of the technical issues of the game, improving upon the combat, and providing additional end-game options to boost subscription numbers more permanently.