Because of the hard limits on contribution, it's virtually impossible for an individual person to do anything on /r/place. What's needed are hundreds of collaborators. And because the creation of something with any degree of order or meaning requires the common adoption of a rule, the way various parts of the canvas are claimed and transformed is reflective of the communities at work. The rule "expand the blue corner" is easy to follow—everyone on board with this goal simply places blue pixels as often as possible to guard and expand the blue corner of the canvas. But when the expansion of their territory outstrips the fluctuating number of supporters, the blue corner can collapse and be overwritten by other groups with other rules. The size, complexity, tidiness, and duration of a given design seem together to be the best measure of the community behind it. /r/prequelmemes has claimed a huge portion of the canvas for a very tidy quotation from Revenge of the Sith. The German flag at one point expanded to envelop the adjacent French flag, which was forced to recreate itself by shifting upwards. The void (an expanding black hole near the center of the canvas) was getting quite large before it became the background for a pink floyd themed piece. Etc.
Organization, commitment, manpower, clarity of principle — these are the determining factors here.