In February 2012 we started noticing a large influx of new comment-spam coming into our sites.middlebury.edu WordPress system that the built-in anti-spam plugins weren’t able to handle. To combat this annoying plague we created a new plugin that instantly killed any comments trying to submit an “author URL” along with the “author name” and “comment text” now that the “author URL” field is hidden.

In the year and a half since this plugin has been in place across our blog network it has blocked an average of 40,000 spam comments every month.

+------+-------+--------------+
| year | month | spam blocked |
+------+-------+--------------+
| 2012 |     3 |       14,814 |
| 2012 |     4 |       19,956 |
| 2012 |     5 |       18,225 |
| 2012 |     6 |       15,937 |
| 2012 |     7 |       29,232 |
| 2012 |     8 |       24,073 |
| 2012 |     9 |       25,973 |
| 2012 |    10 |       42,514 |
| 2012 |    11 |       49,265 |
| 2012 |    12 |      106,128 |
| 2013 |     1 |      103,850 |
| 2013 |     2 |       72,944 |
| 2013 |     3 |       38,336 |
| 2013 |     4 |       35,125 |
| 2013 |     5 |       32,975 |
| 2013 |     6 |       35,011 |
| 2013 |     7 |       28,218 |
+------+-------+--------------+

While some spam is bound to get past any automated filtering, we hope that these efforts have alleviated most of the hassle of dealing with spam comments in WordPress.