Promoting the opposing side, is a lot of hard work, with results that tend towards being disappointing for the effort expended.
you end up putting in a whole lot of effort, and then a few months in, you find out that you are the only people on that side, and people other than yourselves who are interested in that side are few and far between, and do not seem to stick around.
so you step back, because paranoia and lack of self-confidence makes you question whether you are part of the problem or part of the solution. Then you observe that your step back has made the situation worse.
So you get back in, because you have the idea that other people are reliant on you to be the thing that their characters are against. So you rationalise it and think "someone has to be the bad dudes, someone has to play the best supporting actor, and there's no one else willing to do so".
Then you end up with a head full of OOC knowledge, that only brings you pain, because you know that the RP enemies need you, to give themselves definition. Its hard to be a vampire hunter when there are no vampires.
Then you think about whether you should jack it all in, because people start queueing up to moan at you OOC because your characters aren't the cardboard stereotypes they need for their self-fanfiction, and you question why you even bother RPing with people instead of at them, because it's not like you're getting paid to do this.
Then people use their information that X and Y characters seem to operate on similar timezones, or use similar IPs, and use this to be snippy and condescending to X because Y is the 'enemy' and it sours the enjoyment that X gets, and disincentivises both X and Y to rp with instead of at people.
So, promoting the opposing side, is a lot of work, for questionable gain.
If you're going to do it at all, then the one doing the promotion, probably should stay away from TS, Ventrilo, forums and other things, because the mod tools that those things have, will make your life needlessly complicated, if/when someone lets it slip that X is Y.