Re: Tikiwiki vs. Sharepoint
DMerkling, our company is in a slightly similar situation, in that we're launching an internal TW site as a cross-divisional platform sponsored by our parent company, and our division's IT department is planning a local Sharepoint rollout. (We also have a third groupware option in Lotus Notes, which has been in use for several years now.) Only a couple of the IT folks have explored the TW installation, and I don't know anyone outside of IT who has yet tried any part of Sharepoint.
The obvious questions about function overlap are being raised, but they won't really be meaningful unless and until Sharepoint (and its wiki features) are fully deployed to all of our corporate divisions, which probably won't be for some time, if at all. The TW site is available to all divisions right now.
One IT manager who has actually taken the time to explore both installations has said that he thinks the two will serve complementary functions, and can coexist just fine. Time will tell, and user preference will play a big role. I'm looking forward to trying out Sharepoint, since they've been talking about implementing it here for several years now, and I've heard Great Things®. However, given the slow adoption here of Lotus Notes' group database templates and the many resultant complaints, I wonder if Sharepoint has the ease-of-use to encourage widespread adoption.