My community (Madoka Magica) was continuously communicating with our neighbors on all sides, ranging from the gigantic PrequelMemes to our right, Canada to our south, Homestuck, the Greek and Turkish flags mentioned in the article (which really were warring for quite a time before the heart appeared), and even tiny little subreddits like the AEIROU who we had to relocate as part of negotiations for our expansion.
There was constant debate about where to expand, who to defend against, who was being a jerk and needed to be wiped out... it was like a game of Diplomacy more than anything else.