It looks like it's mostly just that the job market is getting better overall; there are more jobs across the board. For example, about 9 months ago I looked up the number of jobs for PHP, Rails and Django on various job sites http://news.ycombinator.com/item?id=805931 Here are the old and current numbers compared:

SimplyHired - PHP: 10726 to 15993, Rails: 2553 to 3823, Django: 328 to 926

Startuply - PHP: 280 to 488, Rails: 121 to 230, Django: 35 to 66

StartUpHire - PHP: 458 to 549, Rails: 119 to 152, Django: 9 to 25

http://djangogigs.com/ has new jobs showing up every few days, despite being an ultra-niche site. My experience is that the Django job market has been very healthy for several years now.

I've been a full time Django developer for two years now.