Wait a second. If the IDs are all allocated in a contiguous block, and the author samples the whole space at random—then the estimate will converge to the correct value. If, on the other hand, the IDs are allocated at random, the estimate will also converge to the correct value.
If you believe that there is some structure in YouTube video IDs, that would have no effect on this experiment. It would just reduce the fraction of the total address space that YouTube can use. This is a well-known property of "impure" names, and it means there is a good chance that the IDs have no structure. In other words, the video IDs would be "pure" names.
If you believe that there is some structure in YouTube video IDs, that would have no effect on this experiment. It would just reduce the fraction of the total address space that YouTube can use. This is a well-known property of "impure" names, and it means there is a good chance that the IDs have no structure. In other words, the video IDs would be "pure" names.