Contra cargo-culty urbanism, density and transportation options do not automatically make a place urbanpic.twitter.com/j6bUwDClbg
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Most streets, most blocks, most buildings, most parks, etc, should be small and prolific. No minimum sizes!
The fundamental characteristic of a good city is its air makes you free, if you will: many opportunities/footholds, few barriers to entry
The larger the building blocks of a city are, the further apart they are, the more exclusive and ultimately stagnant
You want a lot of employers relative to employees, not the reverse
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.