On the opposite side of the fence from employers restricting access to social-networking sites such as Facebook and Twitter, ReadWriteWeb conducted an informal search of job listings on craigslist from Nov. 1-18 and tallied how many of them requested that applicants be familiar with Twitter use.

In terms of cities, New York was at the top of the heap with 196 job listings that mentioned Twitter, trailed by San Francisco with 159 and Boston with 115.

The not-very-tweet-friendly cities were Denver with six mentions in ads; Philadelphia with four, Boulder, Colo., with two; and a big fat zero in Bismarck, N.D.