While exploring the depth of my ridiculous referer spam issue, I ran the following simple
query:

mysql> select count(*) as cnt , baseDomain from referer_visitlog where to_days(now()) - 
to_days(visitTime) = 0 group by baseDomain order by cnt desc limit 10 ;
+-----+--------------------------+
| cnt | baseDomain               |
+-----+--------------------------+
| 682 | chikaliresortmalawi.com  |
| 682 | champvilleclub.com       |
| 682 | ceyloncurry.com          |
| 682 | cbmwyo.org               |
| 289 | brittandersondesigns.com |
| 243 | clevelandfyi.com         |
|  50 | google.com               |
|  16 | google.co.uk             |
|   8 | xopy.com                 |
|   6 | search.yahoo.com         |
+-----+--------------------------+
10 rows in set (1.16 sec)

It’s kind of depressing to find just how many people work that hard to try to spam my silly little site.

Addendum: It seems that virtually all my referer spam comes from four distinct IP addresses. They are now in my blacklist. We shall see how long this holds.