That applies only for Common Carriers. Skype is not Common Carrier. It's an Internet Service which ISP's have been deadset on avoiding getting classified as co

That applies only for Common Carriers. Skype is not Common Carrier. It's an Internet Service which ISP's have been deadset on avoiding getting classified as covered under Common Carrier obligations because it would entail, according to them, enormous harm to the profitability of the sector due to the cost of increased regulatory compliance". Telco's/Telephony must provide pen register/tap capability. Internet services as of yet need not. Until you become big enough for Federal LE to start harassing. The relevant regulation in question is CALEA.