As a defense contractor I can see how something can go for $18 million over 5 years, I've had similar projects along those lines.
Figure an average salary of $75k over 5 years gives you 240...but a rule of thumb in the industry is that the salary is actually about a third of what it costs per person...you figure in the equipment cost per person plus overhead, that gives you 80...spread that over 5 years, you have 16 workers for the website. Take about 6 of those workers out and replace them with server cost/network cost/software licenses and that leaves you with a small office of 10 people working on the site from hardware guys keeping the server running to developers and system admins to managers, Human Resources and marketing guys.
So in the end...probably 2 web developers, 1 database guy, 1 hardware guy, 1 system admin, 1 HR person, 1 project lead, 1 manager, 1 secretary and one big boss that got the contract and is working on others.