In MOSS 2007 you can give item level security to your files or
folders in a document library.
1) Lets say you have a normal word document library with the name
worddocuments on your wss site.
2) In this document library you have created a folder with the name
sharedfolderforguestusers.
3) You have given contribute rights to a user with the name user1 to
this folder and limited access right to the overall document library
i.e. the right which will allow the user to only see items that he has
rights to in this document library.
4) lets say we send the link to this document library to the user.
5) user navigates to the document library based on the link and he
can now only see the folder i.e. sharedfolderforguestusers that he has
contribute rights on.
6) what I found out that inside the folder when a user will try to
update any document or delete any document ,he can do that since he has
contribute rights to the folder but when he tries to upload any document
to the folder using the upload.aspx link for the document library he
gets prompted for security.I feel confidently that this has to be a
defect with MOSS 2007.the reason I am mentioning this is because if you open
the open using the link Open with windows Explorer from the Actions
menu and then copy a document to this folder with the authentication of
user1 ,you can upload a document but only when you do the same from
Upload.aspx link,you cant do the same.
I am not sure if you have ever come across this issue.I am using the
RTM edition of SharePoint that released in Novemeber 2006.