Those of us who do B2B email marketing would probably have encountered the situation where a lead is super-excited (e.g. "cool idea," "great concept and nice implementation") the first few contacts but grow cold over time (e.g. "we've been busy in the office, we will notify you when we get to it," "it's on our roadmap, we will get to it soon"). My question is how far do you continue to follow-up? What is your modus operandi, your repeatable process flow, if any?