The Holonet is an interactive feature on the official Star Wars: The Old Republic website that showcases major aspects of the game and their in-universe backgrounds.
The Holonet section on the Classes details the story information around its class as well as combat techniques, apparel, information regarding the two advanced classes and the class's starship and first companion.
The Holonet section on the Planets details the acsessable planets of the Old Republic, detailing climate, political status and a short video showing the terrain and landmarks the player will see on that planet.
Allegiances & factions
This section of the Holonet when compared to the others is quite dated in that since the holonet was introduced it hasn't yet been updated. So far it only gives information regarding the two factions: the Galactic Republic and the Sith Empire and the Jedi Order and the Sith Order.
The Holonet section on the Galactic Timeline provides information regarding the background of TOR's era and what evens lead to this fragilie political environment, teetering on war. Presented by Gnost-Dural there will be 20 videos (with 11 currently released), that spans to over 20,000 years before the game.
This section of the Holonet details the various inhabited of TOR. Split into three groups, sentient, non-sentient and droids as well as a bio-video and screenshot it details where the sepcies is found and if its sentient which faction they are aligned with.
This section details the 6 Starships available to the player. Detaling information about when and why they were built, their role and who built them. There is also a short video tour of the starships and a number of screenshots and concept art.
Holonet homepage on The Old Republic Holonet