There's traditionally been a bunker mentality among the people who secure email. It's us against them, an unseen enemy flinging viruses and spam--little digital grenades that could blow a hole in the CEO's inbox. Companies still need to have shields to block those Net threats, which continue to evolve in devious ways. Spending in this area, in fact, is expected to zoom. The worldwide market for email security products is estimated to grow from $3.5 billion in 2006 to more than $6 billion in 2010, says research firm The Radicati Group. <A HREF="http://www.baselinemag.com/article2/0,1540,2094835,00.asp?kc=CMBSLEMLP022007SCRT">And the underlying problems aren't going away.</A>