The first explanation I think probably depends, as I often say, on the person we're dealing with. Yes, human beings can be quite different from each other, whether by genetics, environment in the womb, or outside of it. And I think it really depends on who you are - how well you'll take antinatalism that is. You may feel enlightened as I did, since I never really planned on passing on my horrible depression to my kids anyway, or crushed as others have, but not enticed by prospect of deluding yourself. But there are two more categories you can divide that further up into: initial pain, and long-term pain. Some people (maybe everyone, I don't particularly know at the moment) can acclimatise after a brief period of collapse after learning of antinatalism, even if said fall was particularly brutal - for others on the other hand, antinatalism may be a constant battle against mind, body and
As for the second reason, there is definitely a grain of truth somewhere in it, in that, one person's 'disappearance' has already been explained away by this. So could mass workload increases across the board be causing this sudden slump? It's not as unlikely as you might think, possibly because of the recession, though again, I know next to nothing about this. What about other factors that may be holding people back? Well, as far as I can tell, we are not all depressed. In fact, the majority of us most likely aren't, though we may have depressive characteristics in thought - well, OF THE VISIBLE POPULATION THIS IS TRUE. Of those invisible viewers of blogs and such along with anonymous commenters, I am not so sure. Depression not equals suicide and vice versa, but the constant bombardment we often subject ourselves to about the evils of the world, it could be argued (though not by me), have caused suicides. Especially since helping someone might not make the world a better place in the long run (utility goes up, person goes on to murder or worse, have a child and continue the cycle etc.), suicide might seem a valid reaction to this harsh, cruel world (depends on whether you value positive utility or not). So while not depressed, people may still go on to commit suicide and hence leave our tight-knit (sort of) little community. There are also numerous other personal reasons as well, like say moving to a country without internet, or something along those lines.
That "Blogs are becoming obsolete!" suggestion sounds seriously flawed. Sure, there are a LOT of videos on youtube, but there are quite a lot of blog posts as well. Not as many, I'm sure, but so long as I have no evidence to suggest that people are just packing up and leaving in favour of video-sharing sites, I suspect it's not really the case unless people really do hate reading nowadays. You see, there are valid advantages to both mediums, and as long as one is lacking in one regard, people are not going to flock to one or the other (unless they have simply become tired of reading (and particularly commenting on) blogs?). In any case, I can only speculate as to what has caused this sudden decline - or perhaps I have been wrong all along. Maybe there is no decline - maybe this is how things normally are, and I joined at a particular time where there was a significant boom.
In any case, brain wasn't SO soaked in piss today, managed to not ramble. Boring post, I assume, but I did not ramble.