I'm a fan of Dave McClure's startup metrics for pirates. It's a simple framework that can make launching a web app or company a little less daunting by breaking the lifecycle of the user into distinct phases.
I'm also a fan of putting your entire business on a single piece of paper. If you can't outline your business on a the back of a napkin, I think it's likely that you've either made it unecessarily complicated or missed how to best communicate it. If the person across the table doesn't get it, your team members might not get it either.
At INSIDR, we actually use the lifecycle approach to map the entire business as we test, trial and iterate through different strategies of acquisition, activation, referral, retention and revenue - outlining them on a single sheet of paper:
In the diagram above, the dotted boxes represent ideas for different acquisition sources, features, revenue models, etc, and the solid boxes represent what's commited, launched and being tested. GREEN means the strategies are working, RED means they aren't, and YELLOW means we don't yet know. Coupled with metrics, it gives a good high-level view of the entire business but more importantly, it becomes a high-level test matrix for the entire business, keeping the emphasis on tesing and trialing to success.
We don't worry much about the reds, because you only need a single green box across each stage of the lifecycle to build a big business. We worry more about the yellows and aggresively pushing them to red or to green, since a partially successful effort can waste time and money and distract from other initiatives that could be much bigger levers.
Bottom line :: Turning the strategic framework into a day-to-day operational doc has kept our eye on the entire lifecycle and made trial and error a core discipline for the team.