A confluence of trends is apparently heavily fueling VPN service use.Infonetics Research's annual market size and forecast report, "VPN and Security Services," indicates that user mobility combined with the perceived productivity benefits associated with remote and mobile access and the fear associated with continuous new security threats are driving enterprises to increasingly invest in VPN services.According to the researcher, worldwide VPN services revenue totaled $18 billion in 2003 but is expected to grow to more than $30 billion in 2008. The firm cites the complexity of deploying VPNs organization-wide as another primary driver for growth in VPN service revenue.The more distributed, remote and mobile the workforce, the greater the risk and exposure to data theft and network infection - and the more difficult it is for the IT department to control those risks. Therefore, hooking up with a security outsourcing partner becomes a natural step for many enterprises.We wonder, at some point, just what "corporate headquarters" for some large companies will look like? There will always be a need for manufacturing plants and warehouses where actual products are assembled, stored and shipped.But for the "carpeted" areas housing white-collar professionals, will corporate headquarters someday simply consist of mirrored data centers plus a building with meeting rooms - rather than a large campus of buildings with cubicles and offices - and a VPN perhaps connecting small satellite offices and home offices?It seems that many of the large, multiple-building campuses are turning into small ghost towns as the percentage of traveling and teleworking employees continues to rise. Nearly one-third of the U.S. workforce - 44 million people - is expected to work from home this year, up 4% from last year, according to In-Stat\/MDR.At some point, will employers decide that the oft-empty real estate isn't worth it?A couple of other sample data points from the Infinity's study:\u00a0* For every $1 spent on VPN products, about $10 is spent on VPN services.* IP Security (IPSec) is the dominant technology used for delivering VPN services today. By 2008, however, Infonetics expects IPSec revenue to drops significantly, while use of Multi-protocol Label Switching, MPLS with IPSec, and Secure Sockets Layer will all rise.