  This study discusses choice behavior using a voting model in which voters can
obtain information from a finite number of previous $r$ voters. Voters vote for
a candidate with a probability proportional to the previous vote ratio, which
is visible to the voters. We obtain the Pitman sampling formula as the
equilibrium distribution of $r$ votes. We present the model as a process of
posting on a bulletin board system, 2ch.net, where users can choose one of many
threads to create a post. We explore how this choice depends on the last $r$
posts and the distribution of these last $r$ posts across threads. We conclude
that the posting process is described by our voting model with analog herders
for a small $r$, which might correspond to the time horizon of users'
responses.
