Most "inside information" is spread by watercooler talk anyway -- which is a lot less common when products are separated by building.

The number one source for insider Microsoft information is Microsoft interns. Why? We're in almost every product division in Microsoft and we have our own inter-departmental social groups. I heard of some serious insider information not just on MS, but on Intel, Nvidia, etc. just from hanging out and drinking with the other interns on weekends.