In the spirit of Shog9's recent post, "2016: A year in closing", I thought I'd do something similar for spam. Ladies and gentlemen, I present you with all the statistics about spam you never needed to know.
The Big Number
Network-wide, we saw at least 32,462 spam posts last year. There may be more that aren't in my data, but that's not likely to be many. However, you can offset that with the fact that we see around 100,000 posts created or updated each day.
Posts by Site
Stack Overflow, unsurprisingly, gets the majority of spam. These numbers have been consistent for a while, but started changing towards the end of the year, with Ask Different in particular trending up, and Meta Stack Exchange down.
+-----------+------------------------------------------+
| PctOnSite | SiteName |
+-----------+------------------------------------------+
| 26.6106% | Stack Overflow |
| 10.6072% | Drupal Answers |
| 10.2012% | Super User |
| 8.7430% | Ask Ubuntu |
| 3.4621% | Meta Stack Exchange |
| 3.1297% | Information Security |
| 2.4006% | Arqade |
| 2.3477% | Ask Different |
| 2.1702% | The Workplace |
| 1.7849% | Personal Finance & Money |
| 1.4109% | Android Enthusiasts |
| 1.2787% | English Language & Usage |
| 1.2617% | Travel |
| 1.2258% | Mathematics |
| 1.1805% | Graphic Design |
| 0.9784% | Web Applications |
| 0.8575% | Movies & TV |
| 0.8292% | Arduino |
| 0.6686% | MathOverflow |
| 0.6214% | Electrical Engineering |
+-----------+------------------------------------------+
Truncated to top 20 sites. View full data.
Posts by Time
Make what you will of this. The majority of spam is posted between 0400-1100 UTC each day.
+----------+-----------+
| AvgPosts | HourOfDay |
+----------+-----------+
| 512 | 0 |
| 567 | 1 |
| 587 | 2 |
| 765 | 3 |
| 3596 | 4 |
| 4441 | 5 |
| 4477 | 6 |
| 3518 | 7 |
| 3342 | 8 |
| 3502 | 9 |
| 3373 | 10 |
| 3075 | 11 |
| 1855 | 12 |
| 1178 | 13 |
| 914 | 14 |
| 761 | 15 |
| 748 | 16 |
| 707 | 17 |
| 694 | 18 |
| 665 | 19 |
| 569 | 20 |
| 495 | 21 |
| 510 | 22 |
| 469 | 23 |
+----------+-----------+
Time to Deletion
On average, it takes just over 5 minutes to delete spam at peak time, but it can take over 10 at less busy times of day.
+----------------------+-----------+
| AvgSecondsToDeletion | HourOfDay |
+----------------------+-----------+
| 623.9267 | 0 |
| 604.2301 | 1 |
| 636.0441 | 2 |
| 571.1575 | 3 |
| 473.8658 | 4 |
| 441.3046 | 5 |
| 380.7654 | 6 |
| 369.7099 | 7 |
| 332.5471 | 8 |
| 315.3328 | 9 |
| 301.5370 | 10 |
| 313.2093 | 11 |
| 332.4646 | 12 |
| 354.3419 | 13 |
| 392.5989 | 14 |
| 424.5681 | 15 |
| 421.0383 | 16 |
| 420.2009 | 17 |
| 438.6229 | 18 |
| 461.5307 | 19 |
| 448.5552 | 20 |
| 478.9103 | 21 |
| 543.7133 | 22 |
| 599.4058 | 23 |
+----------------------+-----------+
SmokeDetector
Since this is where the stats come from, it's only fair to give the project some credit. I work on SmokeDetector, which is a bot that identifies possible spam and asks humans to flag and feed back on it. Here's the data that shows it works: there's a heavy correlation between the number of feedbacks the post gets, and how quickly it gets deleted.
+----------------------+---------------+
| AvgSecondsToDeletion | FeedbackCount |
+----------------------+---------------+
| 22978.8568 | 1 |
| 5969.3305 | 2 |
| 2900.3543 | 3 |
| 366.6266 | 4 |
| 328.7800 | 5 |
| 192.9524 | 6 |
| 167.2500 | 7 |
| 25.0000 | 8 |
+----------------------+---------------+
posts,posts_reasons,reasons,feedbacks.