It would great for documentation purposes if you could put documentation links into you block diagram. This would reduce the size of the vi and allow complete documentation of the vi. Very large documents of any type (pdf, dwg,office documents,pics) could quickly be opened from the block diagram. The risk would be moving the document and the link becomes invalid. This risk could be minimized by placing a documentation folder in your labview project.
Duplicate of http://forums.ni.com/t5/LabVIEW-Idea-Exchange/Hyperlink-in-Floating-Comments/idi-p/986485