Thanks for the update Roman, both of those spambots have been banned.
As for why the influx, usual answer is because they're spambots and can create as many multiple accounts as their robot programs can generate.
Another factor is that since they don't usually post any spam, I'm left unable to ban the jerks whose names end in "alex" or "toro" or "zoro" or "juriya" or even the resurgence of the ones whose names end in "jibond". So those tend to proliferate during the early morning hours here at the forums. Only when they actually do post spam am I able to delete their accounts.