Access control is perhaps another issue that comes into play for any system. As journal commenting systems have proven, most researchers are hesitant, if not downright hostile, to the idea of publicly commenting on the works of others. Most researchers do discuss works in smaller, trusted, private groups like within a lab or at a journal club. Useful annotation systems may need to offer the ability to make comments completely personal, privately shared or public.

[comment by David Crotty]

There are significant challenges to digital annotation systems, particularly shared annotation systems. While server space was an issue with Mosaic in the 1990s, this isn’t the critical problem any longer, although at scale an annotation system does require some significant hardware support. The real problem associated with public sharing of annotations is getting the model to work across different devices and systems. Locating a reference point is also a particular challenge when working with reflowable text. In such a context, referring to page 164 doesn’t mean anything, because page numbering often isn’t used and, even if it were, one could size up the font to such a large scale that only three words might appear on a “page”. Similarly, one can’t rely on specific character count within the file, since that could change with minor editorial corrections. Creating a hash string of text characters before and after a reference point also has problems, since text could be repeated (as in song lyrics, or a recurring dream sequence). Also matching the point in a text between the first edition of a book and its annotated, fourth version, for example, creates tremendous matching problems, since there isn’t a widely adopted work identifier to tie together various manifestations of a work. This problem expands as one moves away from simply annotating text to comparing different media expressions. Those who remember showing up at a literature class with a different edition of a book than the teacher was using can relate to these challenges. NISO has a working group that is exploring standards to address the location problem, as a jumping off point for work on this topic, which we hope will feed into the IDPF EPUB3 specification.

Other non-technical problems arise that need to be addressed, such as copyright concerns and privacy. If an annotation system allows the capture of a selection of the referenced text, one might be able to collect all of those disparate snippets to recreate the work in its entirety. Realistically, this is among the least likely of pirate scenarios, but some publishers who have engaged in these discussions have noted it with concern.

The question of sharing is also fraught with complexity. How can one choose to share their annotations selectively — only for some works but not others, or only with some people and not others, or only in certain situations or circumstances? A book club may only want to share their annotations of the work they are discussing with each other. Similarly, users of the system trust their annotations won’t disappear if a service is sold or goes out of business. There currently isn’t a standard format for annotation exports and imports that could be used in such a scenario. As with all online services, the traditional problems of user identification and ID management is another challenge, but one that like the rest of the internet is waiting for a better ID management service.

We need to distinguish personal annotation from social annotation. Much of Todd’s article seems to refer to the latter (note that this sentence refers to the entire article). Social annotation requires far more than placing anchors.

The case I worked on was integrating public comments into a proposed regulation. As things stand one has a hundred page proposal and a stack of comments. Placing anchors is no problem. The problem is many comments do not relate to a specific place in the proposal text so there is no place to put the anchor. This is not a computer problem. It has to do with the nature of human reasoning.

[comment by David Wojick]