A homepage evolves along with a startup's business model.
The first major product launch that I was a part of was the Reverb iPad app. It was still too early for a major site overhaul, so I took an "evolutionary, not revolutionary" approach: redesigning the hero section of the home page, featuring a "desktop" photograph that I shot to feature the app without altering the overall look & feel of the site.
After a few months, the Reverb App was successful enough to justify redesigning the entire site around it. All of our development and marketing effort was dedicated to the app, so it made sense to become one of those companies (like Instagram, Pocket, Flipboard, and many others) where the company is the product. All of the home page content was replaced with sections about the app features, with a promenent section where updates and media attention could be promoted.
A fairly large audience for the app materialized, but plans for monetizing it never did. Our next product was a business intelligence tool that could give large-scale publisher insight in to how audiences were interacting with their content...this was our first attempt at this new B2B-focused business model.
A natural language processing engine is a difficult thing to market. Most people don't know what one is, and of those that do, most don't know why they would want one. Even though our target audience were large companies, we still needed to explain what we could do in a very clear way. The theme "we provide deep insights into your customers" kept coming up, both in this example and the one below.
Alternate version of the one above. The team was split over which one they liked better...we ran this as the home page for a while, then replaced it with the "connects ideas to people" version and moved this to a more specific product page.