Community promotion ads
On graduated sites, a sidebar ad appears on the right side of the screen that points to one of several ads approved by each site's community. On Christianity.SE, the following will be a common sight (note the ad on the right):

There's a fair amount of overlap in interest between Christianity and Latin, thanks to the writings of many of the church fathers and the ongoing use of Latin in Catholicism. Thus, an ad like this reaches an audience that is likely to be more interested in Latin than the general populace. But, there are a few issues:
- To my knowledge, Christianity.SE is the only site where Latin.SE has been promoted in this way. One other candidate that comes to mind would be English Language & Usage. Other sites, like Linguistics, History, Spanish, Portuguese, etc., couldn't show such an ad because they are still in beta.
- In order for the ad to appear on these sites, someone needs to design it, post it in the relevant meta post on the target site, and attract six upvotes. Ideally, ads should be visually appealing and simultaneously indicate why members of the target site might also be interested in Latin.SE.
So if you have ideas for new ads, are willing to design them, or are simply interested in upvoting one submitted by someone else, that's great! Hopefully we can leverage this built-in feature to expose our site to more people.