Can't wikipedia's heritage 'metric' also be a factor of hours humans have, in general, enjoyed it (in the broader sense, as in use, derive benefit from)?

There's millions of man-hours of heritage. I don't have data to back me up, but I'd wager more time and effort has been spent in building Wikipedia than in any World Heritage, maybe more than all of them combined. But I don't really know what difference would it make if it became a World Heritage.

Umm according this link http://eandt.theiet.org/magazine/2011/01/pyramid-at-giza.cfm the figure for the Great Pyramid at Giza is 3.5 billion man hours. Wikipedia has aroun 18 million articles. Assuming 2 hours per article, fair enough since most of these are 1-2 para stubs, that's not much.

That information seems pretty suspect to me. They are assuming an average force of 100,000 men working at any one time to reach that figure.

Funny enough, this Wikipedia article gives significantly smaller average work forces:

http://en.wikipedia.org/wiki/Egyptian_pyramid_construction_t...

Yes but even if we assume a figure of 30000 men and a 10 year timeline, that amounts to half a billion man hours. To reach that level Wikipedia should have a total spend of 27 manhours per article which seems improbable. Let alone other projects.