(written from a Production point of view)
Star Trek Online was to have been a persistent, massively multiplayer online role-playing game which was being developed by Verant Interactive (now known as Sony Online Entertainment). Activision would have been the game's publisher.
Announced at a financial meeting in February 2000, it was originally expected to see a release in late 2001 for Windows PCs and PlayStation 2 consoles. However, it wasn't long until the game faced difficulties mere weeks after the initial announcement when Verant decided to drop the title, citing a "conflict of interest" and instead took on LucasArts' Star Wars Online project, which eventually became Star Wars Galaxies.
The idea of a Star Trek Online MMORPG was eventually revived by other companies, first by Perpetual Entertainment and later by Cryptic Studios. Their version of Star Trek Online would see a release in 2010.