Silos of knowledge and expertise build up all to easily, not only as a result of human tendency towards homophily, but also because of more fundamental bandwidth limitations.
As with most human failings, we look to simple technological fixes to resolve them.
One frequently overlooked technology is the use of ambient "side" channels to encourage or enforce communication:
1. Human environment. (Who do you work with).
2. Built environment. (Who do you sit next to).
3. Informational environment. (Where do your documents live).
Every act of sensory perception during the work day is an opportunity for meaningful communication.