So, taking a look at the popularity of 2ch and how significant it is within Japanese internet culture, what exactly are the cultural/social differences that make 2ch so popular and 4-ch so dead (relatively)? Although one could claim it was Densha Otoko that really brought 2ch into the mainstream attention, the fact of the matter is that it was nearly ubiquitous previous to Densha.

Furthermore, what can be done to make 4-ch more popular? I would love to see the board become as strong as 2ch, and although that may not be possible, it would be nice to see a community develop.

It's impossible.

Japanese and Americans have a different mentality. I think Japanese people are usually reserved, and thus need anonymous message boards so that they can finally be themselves.

Americans, however, aren't as reserved, and thus don't really see the advantages of using it.

That's not likely to happen... I mean, when I post on 2ch I get
replies almost instantly.

In this place it sometimes takes days to get a reply.

phpBB and stuff like that are the norm for English speakers and
I can't see that changing anytime soon.