"ThisServer" is hosting multiple domains: www.delegate.org,
delegate.org, ja.delegate.org, dgbeecon.delegate.org, ietf.delegate.org,
mswin.delegate.org, wince.delegate.org, and amakubo.com.
The majority of accessors to /favicon.ico is guessed as human while
the majority of accessors to /robots.txt is guessed as robot.
Although robots are minority in the population (about less than 30%),
seeing the HTTP access log nowadays in 2014,
about 90% or more of hits are made by robots.