linux equivalent for MS sharepoint?

[Robert P. J. Day]

  what would folks recommend as a substitute for microsoft sharepoint?
from the poking around i've done, it seems that one group recommends
something as simple as a wiki, while another camp says "zope".  any
other options?

rday

p.s.  is there a more appropriate venue to discuss just linux-based
apps?  you know, where people can ask questions like, "what can i use
on linux instead of MS XYZ?"