Yeah, I've been fighting this group of spammers since the Oscars. SmokeDetector is why it hasn't been seen much by people, but has been a real thorn in the side of the moderators. I managed to convince SE Safety to add a few things to our blocked user input list, which has changed some behavior. Yesterday's NBA-fest was the first real test for whether that was enough to dissuade our spammers.

Some, but not enough.

Considering how fast these usually get swatted down (within 5 minutes in most cases) the only thing that explains their persistence is they're paid by the post, not on results. That's a hard incentive to fight.

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As for what can be done about them: not much.

This is a problem that has to be addressed at the site-engineering level, if not at the Product Owner level, which means moderators are left with advocating. Which I've been doing. Having been through last night's burst, they're already working out the regexes at play and are busting them. They don't care that their posts (usually) get whacked, have a lifespan of minutes, and don't generate any referral traffic. The only way to fight a group that cares so little about results is to make it harder to post at all.

Stack Exchange has been reluctant to work with me on this.