Ask HN: How do you capture and analyse usage patterns on your RIA?

Hello everyone,

I want to answer the question: "What is the user activity most likely to lead to the user upgrading?"

What are the best practices for capturing potentially large amounts of usage data (e.g., perhaps, capturing every click on every button?), storing it cost-effectively without swamping your main app db, and then running reports/analysis on that data?

Is it best to log this stuff to text and then run a parser to load it into a separate db? To use external services (which ones work best? why?) To store it in your main db? Is it best to capture ALL the data and then figure out what you want to extract out of it later? Is that practical/realistic? Is it better to just focus on specific hypotheses and just record those specific data points?

I'm particularly interested in these questions in the context of a Rich Internet Application - i.e. something that looks more like a desktop app than like a website. Website analytics are fairly well documented, with plenty of articles tools, etc, but I haven't found much on the topic of doing this kind of tracking for complex RIAs that don't have simple and/or obvious conversion funnels.

For example, if you built an application like Huddle, how would you record data to figure out interesting usage patterns and which ones are more likely to lead to a purchase?

Thanks for any input/insight!