Glenn had thought of his life insurance purely as a protection plan. The anti-avoidance rules, risks and general restriction of tax benefits applicable to most shelters prompted him to take a new look at his life insurance for tax deferral as well.
A type of policy, called Universal Life, separates the cost of insurance and the "savings" element of your premium. You know how much of it is being invested and how much interest it's earning. Premiums are flexible, so you can choose how much goes into savings, within certain limits. The big bonus is that it receives more favorable tax treatment than a similar outside investment.