I went to some of the first Sharepoint implementation tutorials at Microsoft campus in Reading UK when it launched. They had some really good ideas for getting people out of the "shared folder" to the Sharepoint repository.

The main thing was doing a search index on the shared folder so that people searching in Sharepoint found the stuff that was still in the "shared folder".

The other bit to the main thing was making the shared folder read only!

I think however that the main reason Sharepoint hasn't taken off is that it is a responsibility much like any website content and it needs to be managed. It's difficult enough getting a company to find someone to look after it's main website content, now with Sharepoint, it's possible for each department to have it's own little web portal....