We weren't the only ones wondering about this. More than one reader was curious about the phrasing the press release: "Already, over 1 million Star Trek fans have created accounts at the official websites." IncGamers was able to get a response from Cryptic regarding the specifics of the release, minus the lingo.
While the phrase "Star Trek fans" led many people to assume that the press release referred to Star Trek Online accounts only. The press release actually referred to Cryptic accounts -- which are required to play not only Star Trek Online, but Champions Online as well.
One million registered accounts is a milestone worth mentioning in any situation, but it's always helpful to know for certain what we're congratulating.