How does vBulletin rank results for search engines?

[Northward]

At times when searching Google, a vBulletin forum may group results. I've attached an example to this thread. The example is vBulletin 3.8.7

How is vBulletin ranking the results to show in Google? Why is one thread the heading and the other threads 'subresults.'

[Wayne Luke]

That is something Google does due to the site and search terms. vBulletin doesn't have control over that. When vBulletin generates a sitemap, all threads have the same priority.