I removed all the harder challenges, so y'all can now stop complaining. Sorry.

There are now only 2 simple questions. Pull requests welcome.

On Thursday, 4 December 2014 at 02:48:07 UTC, MattCoder wrote:
> On Tuesday, 2 December 2014 at 21:41:28 UTC, Vladimir Panteleev wrote:
>> Although forum.dlang.org has had a spam check and used reCAPTCHA since it was announced, it is only somewhat effective against fully-automated bots - it is powerless against humans paid to post spamverts on forums web-wide, which is what the current spam economy seems to be gravitating towards.
>
> Coincidence? :)
>
> http://googleonlinesecurity.blogspot.com.br/2014/12/are-you-robot-introducing-no-captcha.html

Yep. I've heard about it, but it would still allow non-bot spammers in.

On Thursday, 4 December 2014 at 02:29:39 UTC, Faux Amis wrote:
> This has to be a joke!
>
> I couldn't answer a single question:
>
>> What is the name of the D language syntax feature illustrated in the following fragment of D code?
>>
>> string a = x"5095 f9 95d723c2";
> Seems like hex to me
>
>> What is the name of the D language syntax feature illustrated in the following fragment of D code?
>>
>> /+ t = w * g; /+ t = 47; +/ +/
> Those look like comments to me

The test doesn't differentiate between human and robot. It tries to differentiate between human wanting to learn D and one not wanting.

On Wednesday, 3 December 2014 at 19:42:39 UTC, Ary Borenszweig wrote:
> On 12/2/14, 6:41 PM, Vladimir Panteleev wrote:
>
>> Enter DCaptcha
>
> I think this could work with just two or three variants of a question. Always ask what's the return value of the function.
>
> 1. int foo() { return 8 % 3; }
>
> I don't think non-programmers know what that '%' symbol is, but programmers of any language would recognize this.
>
> 2. int foo() { int x = 8; x++; x++; return x; }
>
> I don't think non-programmers would guess ++ is increment, but programmers most probably know it.

These are very similar to two of the existing challenges.

> 3. bool foo() { return 42 != 30 };
>
> I don't think non-programmers know what "!=" is.

This one has the issue that it can have only two possible answers. Should one spammer learn that "true" is a possible answer, they can have 50% success solving this question. (Probably not an issue in practice, considering there are other challenges, though).

On Thursday, 4 December 2014 at 04:02:49 UTC, Mike wrote:
> I had to maintain a technical forum last year that was getting spammed like crazy.  I added the question "how many bits are in a byte?", and the spam vanished.  Based on that experience, I think the bar can be set very low.

The Wiki had a similar question before DCaptcha. Got spammed.

On Thursday, 4 December 2014 at 08:20:27 UTC, Kagamin wrote:
> On Thursday, 4 December 2014 at 02:29:39 UTC, Faux Amis wrote:

> tries to differentiate between human wanting to learn D and one not wanting.

the latter is just a myth...

On Thursday, 4 December 2014 at 10:39:25 UTC, eles wrote:
> On Thursday, 4 December 2014 at 08:20:27 UTC, Kagamin wrote:
>> On Thursday, 4 December 2014 at 02:29:39 UTC, Faux Amis wrote:
>
>> tries to differentiate between human wanting to learn D and one not wanting.
>
> the latter is just a myth...

LOL

Hijacking this thread. Captcha is still not working on https :(

On Tuesday, 9 December 2014 at 18:23:26 UTC, deadalnix wrote:
> Hijacking this thread. Captcha is still not working on https :(

Sorry, had to revert to an earlier version due to an unrelated regression. It's back on reCaptcha now.

The new one should work on HTTPS once I'll find and fix the regression, though.

On 12/02/2014 10:41 PM, Vladimir Panteleev wrote:
> Although forum.dlang.org has had a spam check and used reCAPTCHA since
> it was announced, it is only somewhat effective against fully-automated
> bots - it is powerless against humans paid to post spamverts on forums
> web-wide, which is what the current spam economy seems to be gravitating
> towards.

Ha ha, my first thought was, can't you use something else than reCAPTCHA, which is also known for tracking.

Good idea, but the demo site is down right now :(.
http://wiki.dlang.org/extensions/DCaptcha/demo.php