So here is what this particular project does:
Many tweets have GPS coordinates embedded in them. Shindelman and Larson exploited those geographic points by traveling to the spot of the tweet and snapping a photograph.
and in fact, rather than give the twitter user credit (let alone ask for permission):
Shindelman and Larson made no effort to contact the tweet writers, instead opting for as much anonymity as possible.http://onlineathens.com/local-news/2013-01-26/uga-lecturer-creates-art-tweets
An interesting thought - Twitter is anonymous but not really. We all have usernames and profiles. (whether we choose to be honest or fill them out properly is another story). If someone used a blog post for me in art or any other media, I would probably want at least a credit (tho I suppose if it was highly negative or critical of me, perhaps, not? I dunno.) On the other hand, a lot of what is said on Twitter is generic and probably 2 million other people said the same thing at the same place... but being irrelevant doesn't really change things. ;-)
Twitter terms of service (snipped on 1/25/2013):
You retain your rights to any Content you submit, post or display on or through the Services. By submitting, posting or displaying Content on or through the Services, you grant us a worldwide, non-exclusive, royalty-free license (with the right to sublicense) to use, copy, reproduce, process, adapt, modify, publish, transmit, display and distribute such Content in any and all media or distribution methods (now known or later developed).
Tip This license is you authorizing us to make your Tweets available to the rest of the world and to let others do the same.
You agree that this license includes the right for Twitter to provide, promote, and improve the Services and to make Content submitted to or through the Services available to other companies, organizations or individuals who partner with Twitter for the syndication, broadcast, distribution or publication of such Content on other media and services, subject to our terms and conditions for such Content use.
Tip Twitter has an evolving set of rules for how ecosystem partners can interact with your Content. These rules exist to enable an open ecosystem with your rights in mind. But what’s yours is yours – you own your Content (and your photos are part of that Content).
(Bold is my emphasis)
I really really try to read the TOS but each site has a TOS that seems to be a confusing pot of legalese (I'm not sure Twitter 'tips' help or hurt - they seem to confuse the situation more to me). Certainly, I'm no copyright or licensing lawyer, either. Does "media" include print based art projects though? If not, what makes it different? At what point are we going to get beyond the carrier of content (digital, print, microfilmed, whatever)? As for the 3rd party aspect, it seems that at least in Twitter's TOS, it is clear that is those that partner (whatever that means exactly) with Twitter. Retweet (RT) tweets (republishing a tweet via twitter) seems to fall cleary into TOS (Twitter user to Twitter user). Republishing outside of twitter using a 3rd party tool via the Twitter API or archiving Tweets via the Library of Congress would then seem to fall into partner aspect. However, creating something new from Twitter by selectively choosing tweets? I dunno but it is interesting to think about how much content twitter has and how it could be used to create new works of art