That is the folder where Office stores the "cace" of installation files on your system.  During the install of Office,  it should have asked you if you wnated to cache the install files locally.  This allows Office to quickly install the "Install on first use" components without asking fo rthe CD when it does that.  If you delete it,  then Office will have to ask you for your CD if it needs t oinstall or repair any components.

Ah, thanks. Just out of curiousity, why didn't Office install everything from that MSOCache folder? If during the installation, the user says runs everything from HD, the user most likely wants every feature installed and won't mind the extra disk space. The MSOCache folder is there just taking up space (and slows things down during the occasional install on demand). So what's the intention behind this folder being there? The only reason I can think of is that the contents of this MSOCache folder is somehow compressed and that install everything from it would take up a lot more disk space than the MSOCache itself. Is this correct?