Peering decisions between Internet Service Providers contain substantial non-measurable aspects requiring trust and informal cooperation among peering partners. We study whether spatial agglomeration is observed between Internet peers. Our empirical analysis of the bilateral peering decisions at the Milan Internet Exchange confirms that these decisions are significantly influenced by: travel time between ISPs headquarters- a proxy for distance, bandwidth- a proxy for size, and European connectivity. Proximity still plays a role in reducing the transaction costs of monitoring and punishing deviant behavior within an industry were co-operation is essential for efficient traffic exchanges required by the Internet universal connectivity.