The Elder Scrolls Online, the MMO being made from Bethesda Softworks' hugely successful expansive single player franchise, has had several limited beta weekends so far over the past year. These were smaller in scale, inviting a select number of people to play test the game for free and report their experiences.
This weekend, Bethesda is increasing the scale on the tests without going to a beta fully open to the public. It's still invite-only, but they've started sending out a lot more codes than they have been. In addition, those who get an invite will get an extra to give to a friend, further increasing the number of players.
The game's website states, "This weekend, we're inviting millions to test The Elder Scrolls Online!" According to the team, the November beta had around 300,000 players in the game during a 48 hour period--increasing the number to millions is a pretty sizable jump.
The developers presumably want to test how their system and servers hold up under an increased player load, trying to get a feel for how the game will behave once its available for the public to purchase.
Of note is also that there is no more NDA (non-disclosure agreement), meaning players in the beta are free to upload videos, pictures, and impressions throughout their time playing.
The Elder Scrolls Online will be available for PC and Mac April 4, 2014, and will also arrive on Xbox One and PlayStation 4 in June. The game requires a subscription fee of $14.99 per month on all platforms. An official trailer for the MMO can be seen below.