* Being around the end of the month during a troubling economic period in the tech industry I'd explain the increase in random messages by guessing that lot of low-level recruiting shops are desperately trying to meet some arbitrary quotas.

* Not saying you can't ever find a job with them, but these kinds of recruiters are almost always bad communicators, pushy, disrespectful of social norms, have questionable motives, barely understand anything about the tech they're recruiting for to the point of even getting the names of technologies they're looking for wrong, and are rarely worth dealing with.