Its an interesting question to ponder and assuming for a moment its more than just seasonal variation there are a number for factors at play, here are some I can think of
- Paper based media is effectively dead (I think i read that internet advertising has passed print media now in revenue), thus the news cycles and the way people read and adsorb information is radically changing, so perhaps like aikido-l (long time lurker in the 90's) aikiweb isn't quite in the niche it once was.
- Moving from mail based (listserv) to forum based to web 2.0 seems to be a progression in general?
- Internet usage by portable devices has overtaken desktop devices. Portable devices seem to be used more 'on the go' and favour shorter exchanges and less verbose communications. Hit 'like' if you agree and put some vapid slogan that tugs at a heart string in an image file and watch it go viral
- Online forums/ communities are reflections of real community, if damage is done to the community its reflected in the online version (whats interesting is the aikiweb is one and the same for many)
- People in general seem to be conflict averse, so apart from actual combatants most others will leave the battlefield given half a chance. I've seen this at work in some local aikido online communities in the past. I think no-one likes to watch, pick a side, stand up and be counted or put in the position where they might have to. Where something polarises a community you potentially lose 50% overnight.
- Just a few years ago most dojo didn't have a website, now there is a blog, facebook page and twitter for many. These local communities and blogs are attractive, and less contentious perhaps than something with a more global focus.
- I note many contributors to aikiweb are writing content on their own blogs and reflecting to aikiweb. (self included), and why wouldn't you it builds brand and identity etc. for something more likely to affect the bottom line.
It'd be interesting to see some of the aikiweb stats on engagement, timeline it with some big events in the forums history, global events or just the passage of time to see if anything jumps out.