Hybrid blog comment anti-spam solution continues to work well
In 2013, following a problem with the Akismet service, I decided to implement two additional comment spam protection layers to complement Akismet.
Some of the blogs at work have been getting hammered by comment spam (they use Akismet exclusively), so I went to check how my hybrid solution has been doing, before I again suggest this setup at work.
Since implementing the multi layer solution in 2013, I rarely see comment spam get through (none in the past 6 months), and get just a few moderation notices every few months. Comment spam attempts have grown since 2013, but thanks to the hybrid setup, my Akismet API call volume has held steady at under 200 calls per day, while up to several thousand spam attempts per day get blocked by either Apache mod_access or DNSBL layers.
As the graph below shows, most of the attempted spam since April 2014 has been blocked by the Apache mod_access based layer. Since I still haven't seen any false positives from it, and it substantially reduces my DNSBL and Akismet API call volume, I'm leaving it in place.