Someone buys something in return for something. Transactional sites are about shopping cart conversion, cart size, and abandonment. To be useful, however, it should be a long funnel that includes sources, email metrics, and social media impact.
Someone votes, comments, or creates content for you. Collaboration is about the amount of good content versus bad, and the percent of users that are lurkers versus creators. This is an engagement funnel, and we think it should look something like Charlene Li’s engagement pyramid.
Someone uses your system, and their productivity means they don’t churn or cancel their subscription. SaaS is about time-to-complete-a-task, SLA, and recency of use; and maybe uptime and SLA refunds.
Someone clicks on a banner, pay-per-click ad, or affiliate link. Media is about time on page, pages per visit, and clickthrough rates.
Players pay for additional content, time savings, extra lives, in-game currencies, and so on. Game startups care about Average Revenue Per User Per Month and Lifetime Average Revenue Per User (ARPUs). Games need to solicit payments without spoiling gameplay.
Users buy and install your software on their device. App is about number of users, percentage that have loaded the most recent version, uninstalls, sideloading-versus-appstore, ratings and reviews.