Transacted: A sale has transpired when a contract is signed by both parties. From a salesperson’s perspective, the fulfillment of the contract is the responsibility of other parts of the organization, and the salesperson can now focus on the next opportunity. In the case of early-stage start-ups, however, frequently the person that sells is also involved in fulfilling the contract. A signed contract can be booked as revenue from an accounting perspective.
Qualified prospect: Qualification is the most critical and demanding stage of the sales funnel. In the qualification process, you verify that the prospect has a need for your product, that the prospect sees value in your offering, that there is sufficient budget for a deal, that you have access to the decision-maker, and that there is an agreed-upon timeline for the sales process. The qualification process can be complex and lengthy, and can be managed with a Sales Call Talk Track and stakeholder management chart.
If a sales opportunity does not move down the funnel, the sale will not happen and the opportunity should be removed, hence the “leaky” funnel. A leaky funnel is not necessarily bad; as a salesperson, you want to focus on opportunities that are likely to yield results. It is the nature of sales to have to remove an opportunity from your funnel. It does not mean that you will not sell to that account (a positive action by the customer can put them back into the funnel), but for the time being, you should centre your attention on opportunities that remain in the funnel.
It's no surprise Unbounce is near the top of this list -- they've actually written the book on creating high-converting landing pages. Although there are lots of amazing things about this landing page, the two that I absolutely love are: 1) The use of a chat window instead of a classic form, and 2) the detailed -- but well packaged -- information below the form.

I'm not sure how the algorithm works (or if there's one at all), but while I was filling it out, I had some anxiety about not qualifying. Once I found out I did, I was excited to fill out the form, which I'm sure most people who are in debt and using this tool are. By making this offer seem more exclusive before the form appeared on the landing page, I'd bet that increased conversions pretty significantly.