think university
20,000+ students
1,000+ faculty
500+ admins/staffers

how many need _JUST_ email? (all)
how many need calendaring? (only a few 100)
cell phone / PDA support? (less than 100 - maybe **complete WAG** )
Shared Folders? (couple of 100)
group emails (one for each class taught, for majors, for departments, and so on) billions and billions of combinations

That is what I am investigating this product for...... (our spec calls for a 4% growth rate on email per year)

the AD tree (that i dislike soooo much) has over 20,000 groups at the top level (nesting - weeee dont need no steekin nesting! sayeth the AD admins)

we're about 60/40 PC/Mac with a blossoming Linux populace stealing from both camps - I think my English Dept. just had a faculty ask for a linux boxen this past month....

Backups are important!!!! how is this accomplished?