Maybe you can provide a few examples of what types of videos you are talking about. More than a few things fall under the numbrella of "Social Media Communications"
I saw an interesting animation video by Facebook that was an advertisement within Words-With-Friends. That was gave me the idea to ask this question. Thank you for your reply.
There is a #aftereffects - a good place to search on Twitter and Instagram, http://motionographer.com/ - not limited to AE, Art of the Title - also not limited to AE and a bunch of other sites that show things that have been created with AE. If you are looking for specific examples where AE is used for Social Media promotion then you'll probably have to experiment with Google.
Thank you for your reply.