User blog comment:The Ultimate Thinker/How to catch a Sock Puppet?/@comment-4568327-20140920203334

Aside from the Duck Test and CheckUser, would it be appropriate to set up a venue for, say, "Sockpuppet Investigations"? Wikipedia uses it at WP:SPI. Basically, users that suspect a sockpuppet report it there, and then other editors look at it and begin to monitor the suspect. The Duck Test is used and editing styles are observed. If it is still unclear but it just seems evident that there is a sockpuppet there, a CheckUser may be requested.

It's a very formal process so I don't expect smaller wikis to do this, but on larger wiki in which sockpuppetry is a big problem, this could be plausible.