Short answer: if you need to ask, it's probably too late. Long answer: keep reading.
Many companies gather sales leads on their website by asking visitors to register, perhaps to receive a white paper, register for a webinar, enter a contest, and so forth.
In most cases, the people responsible for selling in those companies wait hours, days, or even weeks before picking up the phone and calling that prospect. It's a pretty stupid move because in most cases, the value of that sales lead (i.e. the likelihood of it resulting in a paying customer) approaches $0 within seconds.
You read that right. Within a minute (60 seconds) an inbound marketing lead is almost worthless.
Here are two charts from a recently released report from the market research firm Software Advice. It tracked the number of qualified leads resulting from callbacks of website visitors who registered for something.
The first chart shows how insanely fast the value of the lead declines within the first minute:
The second chart shows what happens to lead qualification after that minute is up, compared to an average: