Our assignment this week for "Socially Engaged Art and Digital Practice" is to create an online public space. It can be any kind of public space, so long as it is theoretically accessible to anyone.

This got me thinking about the public space of graffiti on walls. The digital spaces we usually think of as public spaces - social media, forums, comment sections, reddit, etc. - have two particular structural characteristics that are completely absent in graffiti. First, that each contribution is separated into its own box, usually tagged with the contributor's identity - although this may be a pseudonym or user handle. A few sites allow anonymous comments, but a widespread need to control abusive behavior, combined with the business incentives of the data economy, have made that affordance increasingly rare. Second, that contributions from the public cannot be removed by other members of the public - only by moderators, administrators, or others with special authority.

In graffiti, a public message is only signed if the contributor chooses to sign it. Anonymity is the norm, with pseudonymity a close runner-up (given the illegality, "real" identity is rare) - and without the digital forensics that the networked structure of the internet allows, a graffiti tag may be harder to de-anonymize than an online handle.

A far more radical difference is the presence vs absence of the enclosing box. The visual language of digital public spaces - each post, comment, or tweet in its own rectangle, all arranged in a grid or a linear "feed" - mirrors the ontology of the digital. Each contribution from the public is atomized, separated, and sorted, even those tagged as "anonymous." Most physical public spaces don't function like this at all. People move freely through a public park, unconfined to any grid or structure. In conversations, debates, or rallies, people may speak over each other or speak as a de-individuated group - consider the difference between a public art performance involving multiple performers, and a video of that performance posted online. The latter, however many people contributed to it, is still posted under a single online handle. Even if every performer involved posted it to their account, they would create multiple posts, each enclosed within its own box.

Graffiti has no enclosing box. This a-separation follows directly from the continuous structure of physical reality, whereas the digital must ultimately capture all information in discrete states: 0 or 1. In graffiti, stylistic similarities may be the only indication that two contributions share an author, or it may be impossible to tell. People directly modify (vs. add comments to), deface, or paint completely over other people's contributions. Which leads to another radical feature of graffiti versus most online public spaces: the direct editing and even erasure of the contributions of other members of the public.

So, I created an online "graffiti wall." Fortunately, the software was already written, though it may not have been used in this way before. Several websites provide online drawing canvas that can be shared with a link and edited by anyone with that link. I used Sketchpad.pro, and embedded my canvas below. Since it's embedded in this public blog, it's a public space. You can draw on it right now. You can add a new page, or you can paint over - or directly erase - what's already there. It's an continuous space (as far as your eye can tell), and your contribution won't be tagged with your identity or enclosed in a separate box. It will overlap and coexist with other's contributions, which you may destroy with impunity, if you desire. Like a physical wall and unlike a potentially infinite social media feed, the limited dimensions of the canvas force you to compete for space with the rest of the public.

It's interesting to note that even this canvas only approximates a physical graffiti wall, and not only because it is, if you zoom in enough, a discrete grid of pixels. When the page first loads, you can see all the past markings on the canvas appear in rapid succession, and then disappear as they are erased or overwritten. This tells me that Sketchpad.pro's software isn't storing the image as a snapshot of the current canvas, but as an edit history, then working out the current state of the canvas by re-playing all the edits. You can only use the undo and redo buttons so long as you don't reload or navigate away from the page - once you do, your contributions are permanent. But somewhere, they're still stored as an edit history - a series of contributions in enclosing boxes, probably tagged with your IP address, arranged in a chronological feed.

But then, until someone sandblasts it away, painted-over graffiti is still a stack of edit histories, laid down in layers on the wall.