Geotagging 100M Twitter accounts, independent of location-sharing preferences [pdf] (arxiv.org)

Impressive work.

Some of the assumptions (people tend to @mention users geographically close to them) don't always hold true, especially in tech, VC, startups, etc.

Previous post and discussion: https://news.ycombinator.com/item?id=9155890

Key quote: However, there do exist several users who have amassed friends dispersed around the globe. For these users, our approach should not be used to infer location.

So yeah.