So now we have to consider the specter of someone writing an overly verbose review of something that reduces to "tl;dr". Someone might summarize the review by writing "tl;dr: tl;dr". Or they might express the same thing, but overly verbosely, so someone might summarize their response by writing "tl;dr: tl;dr: tl;dr". In general, if N "tl;dr"s is a valid sentiment, and any valid sentiment can be expressed overly verbosely, then N+1 "tl;dr"s are a valid sentiment, so by induction any positive integer repetition of "tl;dr"s is valid. However, there exists some number L such that L repetitions of "tl;dr" is itself too long to express the necessary point, and someone who didn't read it would want a summary, the most succinct of which would presumably be "tl;dr: tl;dr nested L times". This meta "tl;dr" itself might be expressed overly verbosely, of course...

thanks - that was helpful to know