As the article notes:
“This map clearly illustrates some fairly big regional divides (more on that in a bit) but it is worth drilling down a bit to see how this plays out at the local level. San Francisco has the largest margin in favor of “beer” tweets (191 compared to 46 for “church”) with Boston (Suffolk county) running a close second. Los Angeles has the distinction of containing the most tweets overall (busy, busy thumbs in Southern California). In contrast, Dallas, Texas wins the FloatingSheep award for most geotagged tweets about “church” with 178 compared to only 83 about “beer.”"
No real surprise here but if one goes into even more details:
“Given the cultural content of the “church” tweets, the clustering of relatively more ”church” than “beer” content in the southeast relative to the north-east suggests that this could be a good way to identify the contours of regional difference. In order to quantify these splits, we ran a Moran’s I test for spatial auto-correlation which proved to be highly significant as well. Without going into too much detail, this test shows which counties with high numbers of church tweets are surrounded by counties with similar patterns (marked in red) and which counties with many beer tweets are surrounded by like-tweeting counties (marked in blue). Intriguingly there is a clear regional (largely north-south split) in tweeting topics which highlights the enduring nature of local cultural practices even when using the latest technologies for communication.”