Every day there are many thousands of domains that are deleted or that expire become available again for purchase. Backordering and drop catching are often confused as the same thing. Whilst they’re very similar if you’re serious about getting a name that other people may want, a drop catching service is usually your safest bet.
Drop catching services have specialised systems for registering expired domain names and usually always succeed in renewing domains worth anything substantial. Backordering on the other hand is offered by most registrars, however, they usually only succeed if none of the drop catchers are competing for the name.
If you have a drop catching service to add to the list, please tell us about it on the resources forum.