Answer:

inboxes

Answer	Crossword Clue
INBOXES	Where work piles up
INBOXES	Places for yet-to-be-answered mail
INBOXES	Trays containing work to do

INBOXES	Workload sites
INBOXES	Where papers may sit
INBOXES	Their contents have yet to be dealt with
INBOXES	Mail receivers
INBOXES	Sources of stress for many modern workers