  In addition to posting news and status updates, many Twitter users post
questions that seek various types of subjective and objective information.
These questions are often labeled with "Q&A" hashtags, such as #lazyweb or
#twoogle. We surveyed Twitter users and found they employ these Q&A hashtags
both as a topical signifier (this tweet needs an answer!) and to reach out to
those beyond their immediate followers (a community of helpful tweeters who
monitor the hashtag). However, our log analysis of thousands of hashtagged Q&A
exchanges reveals that nearly all replies to hashtagged questions come from a
user's immediate follower network, contradicting user's beliefs that they are
tapping into a larger community by tagging their question tweets. This finding
has implications for designing next-generation social search systems that reach
and engage a wide audience of answerers.
