[pmwiki-users] Spam Blocking Proposal

[Wendell Brown]

I am apparently one of several pmwiki users to become a renewed target 
for wiki spam.  And being a firm believer in proactive blocking (ie, 
using shared resources to identify spam because it's a good bet that by 
the time spam gets to me someone else has already identified it) I want 
something that will catch most of it without having to jump through 
hoops.  But, as someone else has pointed out, it's not cool to lose all 
control of what is blocked.

With that in mind, I got to thinking about CAPTCHA 
(http://en.wikipedia.org/wiki/CAPTCHA).  Many sites already use this but 
I'm not generally a real big fan of it because it's pretty invasive for 
real posters, BUT, if it were only required for users with IP addresses 
that show up on a DNS Black List then it wouldn't be invasive for MOST 
users and it should block a lot of bots.

Based on the IP addresses of the spam that I've been getting over the 
last few days, it seems that almost all of the sending IP addresses are 
listed on the SORBS-WEB list (http://www.us.sorbs.net/).  If you are 
getting spam, try the following link and enter the ip address of the 
sender and see if SORBS-WEB doesn't identify the majority of them.

http://www.dnsstuff.com/tools/ip4r.ch?ip=

To be totally honest, I've considered adding this as an option for 
MTBlackList without the CAPTCHA but I'm a bit concerned about false 
positives.