What is polling?
Polling means asking a service for updates at regular intervals. Your app checks again later, even if the last answer was that nothing had changed.
At 10:00, your automation asks for new signups. None yet. Alex submits the form a few seconds later, but the automation does not know that until its next check at 10:01.
That delay is part of polling. Checking every few seconds could find Alex sooner, but it also means more requests, including many with nothing new to return. Those requests can cost money or hit the service’s rate limit, the amount it allows within a period.
Once your automation finds Alex, it adds the spreadsheet row and remembers that signup. Otherwise, the next check could add Alex again.
The useful question is how quickly your project needs to notice a change. That helps you choose a checking interval or consider a webhook.
Your app checks repeatedly and discovers the signup on a later check.
A webhook lets the service notify you and can avoid repeated checks, but providers do not always offer one. Polling is useful when a scheduled check fits the job.