[amcd]

Jafo232, there can be many reasons. Your suggestion about network storage is good if the issue is disk space shortage, but there can be many other issues/objectives.

It may be desirable to run the forums on a multi-carrier, BGP network which costs much more (touted by hosts as premium bandwidth) and the attachments on a lower cost network (value or volume bandwidth).

A big board may want to reduce load on its main webserver by offloading some functions.

A board using shared hosting does not have the option of network mounts, but it can use multiple hosting accounts quite easily if vbulletin is capable of distributed functioning.

Just a few. Hope you get the idea.