It may be the case that this forum is the most popular, however that doesn't necessarily mean that there would be too few people on others. Other than perhaps bitco.in/forum, each of the sources I posted there has hundreds/thousands of users that you can converse with about whatever subject takes your mind. I would certainly say that that is more than enough people to have a decent back and forth, and I personally have had extremely good times on forums with much less of an active population.