During prime time on an average day in an average subscription MMORPG between 10% and 20% of active subscribers are logged on, as an industry rule of thumb. During prime time on release day, the number is much closer to 100%, and only slowly declining from there over the first few weeks. Thus MMORPG servers are usually overcrowded at launch. When this phenomenon was first observed, it took some game companies by surprise. Anarchy Online tried to get everybody who wanted onto the server, leading to the worst launch in MMORPG history, because servers just completely lagged out. Other games had their login server crash. Once game companies realized they had a problem, they invented the login queue, a solution that has been used for many years in many games now. Some companies tried to quickly open more servers, but that inevitably leads to server mergers once the first rush subsides, with a lot of bad press on how the game is failing. So up to SWTOR no game has come up with a better solution than queues.
But it seems that 2012 is the year where developers are rethinking that approach. TERA announced handing out xp bonuses to you while you are waiting in the queue. And now Guild Wars 2 announced overflow servers. Meaning that you get the option to play on a temporary server while there is a queue on your main server. Obviously that limits your options of guild / friend interactions as well as server vs. server warfare, but to level up your character this should work well enough. I'm looking forward to trying this. To me this appears a much better solution than to ask people money for waiting in a queue.