I'm not sure the heuristics are that simple.

The signal-to-noise ratio in Twitter is already low as it is. Most tweets contain links, lots of users are followers but are not followed.

Sure, combining several clever heuristics can reduce spam levels, and no doubt Twitter must attack this aspect if it wants to stay relevant.

But can you put your finger on what exactly constitutes spam in a platform that is so noisy?

It would require more than 30secs thought but I'm sure there are some heuristics which will work. I'm not even convinced the "report spam" button is connected to any action on twitter's server. And why not use blocking as an indicator? Surely if Person A @-replies several people, and they block A, then just disable @-replies from A.

Has anyone tried using a Bayesian filter for twitter spam? These have been very successful for email. In fact, I consider email spam a solved problem now (thanks Gmail!)

It's for things like this that I wish I could insert a proxy between my twitter clients and twitter itself and build my own rules/spam filter.

Sounds like you would prefer a communications medium not running a proprietary protocol controlled by a single company whose business model relies on their ability flake sure you cannot block unwanted content.

I cannot think of a single non-spam case where somebody would @-tweet the same link to a hundred people. That won't capture all spam, but it's a pretty easy low-pass filter.

True. @-tweeting the same message is indeed low hanging fruit. But spam gets sophisticated as the arms race continues.

My assertion is that after a certain point (which we are not far from), Twitter as a platform will have a problem making a distinction between "spam" and "legitimate content".

I think there's definitely potential for an arms-race here (just like there was with email spam) but I don't think it's a reason for twitter to not enter the battle at all.

Also, the @-tweeting is easy to ignore. Yes, you have to check who is replying to you a few more times than you would have, but it's not the end of Twitter.

Where you can see the real problem is when there are trending hashtags that spammers get a hold of... spammers grab hold onto a hashtag and keep it artifically trending long past its relevance.

If not permanent ban, but ban for some time, lets say 5 hours would more helpful IMO.

It won't do a perfect job, and their will be false positives, but the point is, unlike with spam in email - because of their asymmetrical following model, false positives are not nearly as much of a problem. Twitter should absolutely do this.

Twitter could easily detect spammers - by their follow history, reputation score (eg a google-rank link like SVD of the follow graph), or simple ratios like follows vs followers. It will inevitably false flag some people but that's not nearly so much of a problem.

That is, they don't have to outright ban these spammers, all they have to do is block these people from search results available for #hashtags or @replies. In the case of genuine people false flagged as spammers, they can still get their message out to genuine followers. It's not too much of a loss to be banned from search results and @reply messaging until you build your karma level a bit.

You're absolutely right twitter should fix this and do it fast. It's a goddamn shame seeing a potentially very useful public resource - like adhoc organising around #hashtags - being destroyed by the actions of a few.

tl;dr Twitter can starve out the spammers just by blocking search results.

You're totally on the right track.

It's not an all-or-nothing thing. Excluding suspect accounts from @-replies and hashtag search results is a nice low-key way to keep the majority of conversations going. It's also subtle enough that the spammer might not realise that no one is listening.

So why isn't Twitter doing this? Don't they care?

If they do, they're doing an admirable job of keeping it a secret.

There are services that rank twitter users based on interaction. Klout comes to mind. If 3rd party services can measure quality, surely twitter could as well. Granted, it's only one metric, but it's a good place to start.

--edited to remove quotes around the word rank. Not sure why I put them there.

The other issue is gaming Twitter. Anyone who has done lots of Twitter searches can see that several publications have lots of phantom accounts that simultaneously tweet (and that's tweet, not RT) their links to ensure the widest exposure. Porn spam is just one of their worries. The entire system is set up for such corruption.

To be fair, I've seen plenty of spammer accounts that have thousands of followers.

That said: I agree, banning accounts that tweet nothing but the same link would be a really easy step towards reducing the amount of spam. At the same time - maybe Twitter don't want to auto-ban, as this is a quick and easy way of finding spammers. Tricky :-/

>>>To be fair, I've seen plenty of spammer accounts that have thousands of followers.

Lots of accounts are set up just to Follow back anyone who Follows them. I've understood for a long time that Follower counts on Twitter are meaningless.

Not entirely meaningless - I think the important number is the ratio of followers to followees. If somebody's got 1000 followers, but they also follow 1000 people, most likely those are all followbacks, and not indicative of genuine interest. But if somebody's got 1000 followers and and only follow 100 people, they're more likely to be worth your time.

Follower counts as in, "Look how big my dick is."

There’s an alternative to banning outright which is tar-pitting.

At least one of those isn't true, my "work" Twitter account is mainly links and a short comment from me for example. Each of your criteria only affects the probability than an account is a spammer. E.g. you could easily organize a campaign of "spam report" on a hated celebrity, politician, whoever and get them booted.

Your work twitter account tweets the same link over and over again? That's pretty odd and frankly doesn't sound like a good use of twitter.

But @-replying or tweeting the same link to different hashtags? Spam, spam, spam!

No, of course not! But one of your criteria was a link in every tweet.