If the number active (alive) Facebook users grows at a sufficient exponential rate, e.g. each new generation has at least 2× the users of the last generation, then the answer would be “never”

Edit: Um, humans do grow in population in an exponential pattern… how long do you think the population has been at 6.8 billion?

Well, populations are typically modeled as a sigmoid function, they only appear to be growing exponentially. I think it's fair to assume total population will stabilise whilst we are still resource limited to Earth.

It seems that we are at the inflection point of the sigmoid:

http://upload.wikimedia.org/wikipedia/commons/7/77/World-Pop...

The last estimate I seem to find on the subject said that the population should level off at 10 billion in 2200. Granted, this is from 1999: http://www.un.org/esa/population/publications/sixbillion/six...

Reassuring to see that the UN doesn't predict any large discontinuities in that graph

Last I checked humans are limited in supply. AI users though...

Currently there are many zero AIs, as far as we know.

Humans do not necessarily reproduce exponentially. Hans Rosling's TED talks feature, as a central theme, that the population can stabilize at 9 billion with the right initiatives and social changes. http://www.ted.com/talks/hans_rosling_on_global_population_g...

My post starts with "If". (I imagine the possibility of a singularity and the consequent interstellar expansions and/or virtual entities.)

According to world population on wikipedia it seems like more people live now than have died since year 1.

I read that this is an urban myth and actually only a few percent of the people who have ever lived are alive today.

Ever lived != lived since year 1. That said I just looked at the table on wikipedia and did some simple calculations. In any case even if more people died since year 1 than are alive today, not many more died.

If you take ALL deaths, that does greatly outnumber the people alive today.

sounds like a movie.. i like how you think.