When we talk about the processes necessary to create a very large Web system, it will get technical. And when you're selling a Web system to a client that doesn't understand all things technical, it's tempting to make things simple. Just think of it in real-world terminology, like you're designing and building a house. Draw up the blueprints, hire the builder, pick up the wood from the Home Depot, and hammer it together with some contractors. Sign on the dotted line and we'll get cracking.
Well, that kind of analogy isn't quite appropriate for building complex Web systems, and makes things harder in the long run with a less sophisticated client. Sure, we have our information architecture and our wireframes, our technical briefs and database designs, our UI comps and our testing plans. But if we've done our job well, we haven't made a house. A Web system is an organism. A brochureware site that won't be touched for years is a tract home in Denver.
Please avoid this metaphor in your proposals. It makes it sound like you're just selling them a product. And you aren't.