Unfortunately, Twitter users have been slow to adopt geospatial features: in a random sample of over 1 million Twitter users, only 26% have listed a user location as granular as a city name (e.g., Los Angeles, CA); the rest are overly general (e.g., California), missing altogether, or nonsensical (e.g., Wonderland). In addition, Twitter began supporting per-tweet geo-tagging in August 2009. Unlike user location (which is a single location associated with a user and listed in each Twitter user’s profile), this per-tweet geo-tagging promises extremely fine-tuned Twitter user tracking by associating each tweet with a latitude and longitude. Our sample shows, however, that fewer than 0.42% of all tweets actually use this functionality. Together, the lack of user adoption of geo-based features per user or per tweet signals that the promise of Twitter as a location-based sensing system may have only limited reach and impact.