On Tue, Jul 30, 2013 at 04:40:42PM +0200, Arturo Servin wrote: > Captchas? Recaptchas? Captchas et.al. are completely worthless. They're defeated at will by the first adversary who comes along that's willing to expend the minimal resources required to overcome them. The best methods for blog comment abuse control seem to be combinations of network/domain blocks and moderation. Both have their downsides, though; the former needs to be custom-crafted for each particular application and the latter can be time-intensive. The "trick", if there is one, is to use layers of these so that each is conservative about what it blocks (thus keeping the FP rate down) but that each leaves less work for successive layers to handle (thus keeping the FN rate down). ---rsk