A backorder is an attempt to secure an expiring domain if it becomes available at the registry. It doesn't reserve the name and the owner can still renew it. If it does drop, other services may be trying to catch it too. No service can ever guarantee a catch.
That's why domainers often backorder the same domain through several services. It improves your chances of having an order with the service that catches it, though other people may have placed orders there as well. Depending on the service, the domain might go to whoever ordered first, or it might end up in a public or private auction. It's worth knowing how that works, and what you're prepared to pay, before placing a backorder.
Placing backorders with more services also gives more of them a reason to chase the domain, increasing competition.
You might miss out because the owner renews, another service catches the domain, or you lose an auction after your service catches it. What happens to your order then depends on the service. Some won't charge you; others let you use your backorder or credit on another domain.
A good rule is to use services that charge only when you secure the domain. With those services, a failed catch or lost auction won't cost you.
What have you learned from a .UK backorder that didn’t work out?
Source: r/DomainParachute · by /u/DomainParachute