As this article notes, "Critics of the PDF also dislike the fact that it permits only passive reading. This means that scientists are not fully able to exploit the dynamic and linked nature of the Web." It seems like a small thing - and in the world of HTML I guess it is - but the world of PDF readers is beginning to move into the real of interaction with live data (including tables and references) with Utopia Documents, developed in 2009 and being released as open source software this week. So, for instance, when a document in Utopoa is opened, "a sidebar opens up on the right-hand side and fills with relevant data from external databases and services like Mendeley, SHERPA/RoMEO, and Wikipedia." This post interviews Utopia developer Steve Pettifer.