In the Customer Service and Support part of Microsoft, you will often see the term funnel. Here are some citations:
Effectively and efficiently solve issues by driving levers across the entire funnel.
Putting the Fun in Funnel.
Strengthening the front of the funnel.
The funnel is a way of viewing customer support engagements. For some reason, the funnel diagram is always drawn on its side with the mouth (the fat part) on the left and the stem (the narrow part) on the right. The width of the funnel represents the volume of customers at that stage of the support process, and the progress through the funnel represents how much time the customer has spent working on a solution.
At the mouth of the funnel are the customers who turn to built-in product help, online help, forums, Knowledge Base articles, blog entries, training materials, and similar resources. A significant percentage of customers get the help they need via self-help, where the solution to their problem existed even before they asked the question; they just had to find it.
The funnel narrows, and the customer picks up the phone or otherwise initiates a support incident. A support technician helps the customer via email, live chat, phone call, whatever. Another percentage of customers get their problem solved at this stage. It took longer, but the problem did get solved.
At the stem of the funnel are the customers whose problems remain unresolved, and now things get bad. The problem takes days to resolve, multiple engineers get involved, and maybe even a site visit is called for.
There is a concerted effort to improve the support resources at the front of the funnel. Of course, there are efforts to improve the support process at all of the stages, but the front of the funnel is a particular area of focus, since that's where everybody starts out, and that's where most users get their solutions. The term front of the funnel is in such heavy use it even gets its own acronym: FoF. Is it pronounced foff? Beats me.