One of my very good colleagues, Asim at Templeton Green Business coaching tweeted recently along the lines, "Do you think of sales as a funnel or a pipeline?"
Twitter is a distracting world of sometimes pointless chattering but depending on who you're listening to, the chattering or tweets can be thought provoking, challenging and can sometimes get you some business. The best person to speak to about twitter and how to make it work for you is Katie Anderson at Katie Anderson Blogs but I digress a little.
Do you know what I mean when referring to sales as a funnel or pipeline? No?
When you google "Sales Funnel" this is one of the results you get:
http://www.mindtools.com/pages/article/newLDR_94.htm
Really confusing because the title of the article is "Sales funnel: keeping control of your sales pipeline"(!) so that doesn't particularly help with understanding the difference but pictorially, the example given on that web page is really helpful in understanding the sales funnel. You start with many unqualified prospects and as you operate YOUR sales process, the number of likely customers reduces, until only real customers emerge from the bottom of the funnel. While it works superficially on a visual basis, it implies that there are filters through which some prospects do not pass. So what happens to them? Do they just sit there, like Vladimir and Estragon waiting for Godot?

For me the sales funnel also suggests passivity. You cannot force liquid through a funnel - it takes its own time, governed by gravity and (technical bit now, the viscosity of the liquid itself). So funnels suggest masterly inactivity on the part of the salesteam: the narrowing of the funnel means you can't hurry things along, pushing to get to a sale. And that is quite correct: fast pushy sales people will make sales but they wont last as customers in the long term.
It also suggests that you can pile a huge mixture in at the top and (providing there are filters as the funnel narrows - questioning, relationship building etc), only liquid gold emerges from the bottom.

Pipelines on the other hand are fixed diameter objects (usually) and carry things along at a constant pace - you can't have some things going fast and others going slowly in a pipeline. So using a pipeline as a visual model demands action and energy applied to the sales process, actively moving people through to get to the point of asking for a sale. Interestingly in NEITHER visual model are there waste disposal points where "non-customers" are thrown in the trash. And to an extent the philosophy is correct there - even if you don't sell this time, you might later, when their circumstances change.
So maybe the historic sales process models - funnel and pipeline - are neither of them any good at visually representing what happens in sales.
Speaking entirely from experience now, sales just happen as often as they are controlled. I've had customers turn up and buy, others who hear only a little of the "process" and buy, others who don't buy now but come back later.
So to try to create a graphic or image or model to represent the sales model I think the best image is a multi overlapping venn diagram. The non overlap areas

represent the various populations of prospects and they can move between the pools at their own pleasing before or after being "tagged" by the sales person.
The intersections on the diagram represent either moving closer to a sale in the sales process OR by the prospect choosing to change pools (they are helped to change pools by a great salesperson). This constant movement is what makes neither the funnel or the pipeline a suitable graphic. Visually you cannot "jump" from one end to the other.
In the traditional venn diagram, the overlaps represent belonging to x sets. In my sales diagram, the population in an overlap region represent people in that stage of the sales process but remember the prospect OR the sale person has the power to cause the prospect to change position.
There must be someone who disagrees. So comment!
JohnF