sweet wrote:

This distinction is b/c some users cannot return wu's in less than 2 days.
But this does not make them non-existent - just outside the range of the
definition of "active user."

As it says on the "numusers" page, a user must not have been heard
from for nearly a month (28 days, to be precise) to be dropped from
the "active" list. The two-day work-unit turnover is a separate issue altogether.

Note also that roughly half of the total users haven't returned any
results at all.

See <http://setiathome.ssl.berkeley.edu/userresults.html>.

-- 
Odysseus 17# @ 38Y