The modern variant of the "long tail" can be seen in the force structure of the US counter-insurgency effort in Iraq. This new tail is composed of 120,000 personnel in hundreds of large and small companies that provide everything from traditional support functions to reconstruction to security in Iraq. To be even more accurate, you could also throw in the tens of thousands of Shiite, Kurdish, and tribal militias that US troops rely upon.
If we plot the number of personnel by the source, the resulting curve has the classic long tail distribution pattern. The curve starts with the US military and rapidly drops off as additional groups are added. At the far right hand side of the curve are a plethora of small private military companies, tribal groups, and engineering companies that provide security and reconstruction services.
The good thing about the long tail approach to warfare in Iraq is that it provides a demand driven mechanism for dealing with a rapidly evolving threat. For example, the US State Department can hire private bodyguards from Triple Canopy to defend themselves against assassination and kidnapping (this means that they are not reliant on a bureaucratic US military for protection services and can therefore tailor their purchases to their specific needs). The bad part is that the US military hasn't come to grips with this new way of conducting war. It doesn't provide the platform services necessary to make it work efficiently (exactly what those platform services are will be detailed in my upcoming book).
Unfortunately, the lack of a platform, particularly in the form of legal cover for deployed PMCs, is about to unravel this distribution. The Iraqi government has started to regulate private military companies working in the country. Since the rules governing these personnel are still largely undefined, this regulatory effort will likely result in a distortion of the US military's counter-insurgency market due to rampant corruption and mismanagement by Iraqi authorities.