... whoever manages / monitors this forum and removes the annoying spam health / medical rubbish which appears is doing a fantastic job.
This is for Ubuntu questions, not 411 spam.
Keep up the good work, whoever reads this.
Not to put down Mithrandir's answer or Charcoal which indeed does a terrific job, but it's not only the awesome Charcoal folks and SmokeDetector who keep Ask Ubuntu clear of spam, it's also site moderators and normal users like you and me. Until recently, every spam post had to be flagged by six site users (with at least 15 reputation) or one moderator to be deleted. Now, many spam posts receive 3 automatic flags through a mechanism developed by Charcoal, but they still need flags from human users to be deleted.
If you see a spam post, please flag it! Most of them now disappear at lightning speed, but sometimes, for whatever reason, they end up hanging around for a while. It's up to the site's community to keep the site clean.
Ask Ubuntu is moderated by you.
You're welcome! ;)
We're an organization known as Charcoal, or Charcoal-SE. Check out our website https://charcoal-se.org for some amazing spam detection!
But seriously.... yeah, we're Charcoal, and that's our website. We detect spam all over the Stack Exchange network - not just Ask Ubuntu, but Stack Overflow, Super User, Math.SE, Bitcoin.SE, just to name a few, using a bot named SmokeDetector. Essentially, the bot fetches every single post that's been posted or edited on the network, and puts it through a series of tests - mostly regular expressions developed by users who noticed patterns over the years. All of our code is on GitHub, and we welcome all people who want to help us. Just pop into our chat room, Charcoal HQ ;)
If you're a statistics kind of person:
We've detected a little over 10,000 posts on Ask Ubuntu alone. Over 9,600 of those we determined to be spam. All over the network, we've detected 91,000+ posts, of which roughly ~74,000 were determined to be spam. That's... a lot. And you can find the content of these posts on https://metasmoke.erwaysoftware.com, where we keep them to help us in detecting common spammers and other patterns, and hopefully help us refine our spam checks to be even more accurate.
We're a volunteer organization, not officially supported by Stack Overflow, Inc. We do this because we don't like spam, and to keep browsing the site a better experience for users like you.