Wikipedia gets CAPTCHAs for anonymous edits

Yesterday, image CAPTCHAs were enabled for all anonymous edits on all Wikimedia Foundation wikis (including the popular encyclopedia Wikipedia). I noticed this by chance because I’m in a computer lab right now and found some vandalism on an article linked from the main page, but didn’t want to take the time to log in first. However, by the time I finished typing in the CAPTCHA, an admin had already reverted the vandalism. Drat.

The reason for the CAPTCHA is that we’ve been having some spam problems on-wiki recently, with spammers using automated bots to add links to dozens of pages before they end up being blocked. We have a global spam blacklist that does a good job of stopping spammers dead, but all of their edits still have to be manually reverted, which is a pain. Hopefully this new change will alleviate some of that. This change will basically stop all anonymous bot edits (including legitimate bots that get logged out by accident). It will also stop vandalism bots that are running anonymously, which we’ve seen a few of.

Unfortunately, this change still doesn’t do anything against spamming/vandalism being done using registered user accounts. Yes, you do have to pass an image CAPTCHA to register an account too, but that’s only once per account rather than on every edit, so people could conceivably manually register a bunch of accounts and then hand the account details off to their bots.

What I’d like to see is CAPTCHAs on the first twenty edits of each new user (in addition to each anonymous edit). This would make automated spam/vandalism impossible.

One thing I’m worried about though — are we making the barriers to edit too high? Anonymous edits do contribute significantly towards writing the encyclopedia. There’s a trade-off between making it hard for automated ne’er-do-wells and putting a burden on legitimate editors who just can’t be bothered to login or register an account. I hope we haven’t gone too far in one direction.

Update: It looks like CAPTCHAs have been disabled; read the comments for more information.

7 Responses to “Wikipedia gets CAPTCHAs for anonymous edits”

  1. Tawker Says:

    Really, I just tried and I see one (at least on the main edit page..)

  2. Cyde Weys Says:

    You’re seeing a logged-in CAPTCHA? Are you sure? (Or is that not what you were talking about? It’s hard to know.)

  3. CJ King Says:

    Cyde, I just did an anonymous edit, and I saw no CAPTCHA. Does that mean something?

  4. Cyde Weys Says:

    Yes, it does mean something. I just made an anonymous edit and confirmed that CAPTCHAs have indeed been turned off. I wonder why? It seemed like a good feature. Maybe the CAPTCHAs were too intensive for the servers to handle? Or maybe someone felt that it was raising the barrier to anonymous contributions too high?

    Hopefully we’ll see some sort of announcement on-wiki about this.

  5. Darmok Says:

    If I recall correctly, they were briefly enabled some time last year, as well…only for a day or less, though.

  6. Cyde Weys Says:

    Yeah, I’ve asked the MediaWiki tech mailing list, let’s see what kind of a response I get.

  7. Cyde Weys Says:

    Alright, so I got a response. The answer is that CAPTCHAs are only triggered for anonymous edits that meet certain criteria, such as edits that add an external link (which is what spammers do). I think this is a great solution to the problem because it doesn’t over-burden the vast majority of legitimate anonymous edits.