Classified publishing seem to be popping up all over the place. We’ve recently seen them surface in a number of online communities – both small communities such as Boof as well as big ones like MySpace and sometime soon Facebook (if the rumors are true).We’re also expecting classified listings pop up in blogs. A few people (myself, Rohit Khare, Assaf Arikin) recently proposed a microformat called hListing that would faciliate this. Microformats are a set of simple open data format standards used to implement structured blogging or web microcontent publishing. Part of the idea behind microformats is to “pave cowpaths” – i.e., “standardize and codify emergent, popular behavior on the Web.” Given all the activity swirling around online classifieds over the last few months, seemed like a good time get the conversation rolling on something like hListing.With hListing, classified listings can published in a way that’s easy for search engines to reference them — whether the listings are published in a marketplace platform that supports microformats or a blog. To give people a sense for how this might work in a blog, Assaf created a WordPress plug-in for the draft spec. This is clearly pre-beta stuff but it helps visualize where this could go…