This was discussed on the forums earlier today. People saying that their server said full but did not feel full. That is till one poster suggested they look at the instance of the planet they are on. It became clear that some were seeing a number in the high 30's to low 40's. The servers may not seem full, but that's because you can't see everyone on the same map as you as they are spread out over many copies of that map. Hope this helps.
"The servers are not FULL that are flagged as full. They are clearly trying to spread the load across the servers and to especially spread people away from some of the day 1 servers that attracted big #s.
Wave 1 was only like 100,000 people and they supposedly had 1.8million online for the last open beta weekend so they are very definately easing into production."
From the aussie gamer forums