I don't understand the need some Linux advocates have to kick at the BSD's due to them having less users, it's some weird 'kick downwards' attitude I find appalling and given Linux own underdog history it just makes no sense. At the same time I can't understand the 'f**king Linux ate our lunch' mentality which also exists among some of the BSD advocates. All in all there's no reason why Linux and BSD fans shouldn't be able to get along. Both are open source, both are unix descendants and even though their respective licences certainly differ in terms they both promote the use and development of open source.
BSD isn't going to disappear. While the developers are fewer and the community is smaller than that of Linux, BSD is still going strong after all these years. And here's the thing, you don't have to conquer the market to justify your existance, there's room for smaller players in pretty much all segments (heck, even in the desktop market where Windows has a stranglehold).
And obviously Linux won't disappear either, I don't see it ever becoming a desktop OS for the masses but that doesn't prevent me from using it as my day-to-day OS, meanwhile it's it remains strong in the server/embedded and of late in the mobile space markets (due to Android).
Due to a higher level of developer support (much of which through corporate backing) Linux is developing faster and 'broader' than that of the BSD's, however the BSD's seem more focused on their niche targets and thus are likely very competitive in those particular areas.
They are both great unix-based systems with alot more in common than that which separates them, so can't we just get along?