Outdated Forum Sitelinks


Forum sitelinks have been introduced by Google in 2009, but not even the Google example in their blog works anymore.I am still trying to figure out why some older forum thread sitelinks get pulled and some more relevant or more recent aren't. 

Any ideas why some sites e.g. Yelp always get these (outdated) sitelinks while other massive sites with similiar content aren't? Possibly authority of domain, deep links, sitemap, board software?

Any thoughts?