comments aren't quite worthless
Who should own comments?. If nobody owns the writing (or if each entry is owned by its author), that pretty much guarantees that the whole lot will be tossed into the garbage sooner or later. [Mark Bernstein]
It isn't rendered worthless, but the subjective value does not get transformed into objective value. Thus when the subjective value of the pursute disappears, the real value approaches the point where they may be 'trashed'. However, then we have the problem of author-owner vs audience-owner….