If I have no use for it any more, why not throw it back in the pool? Someone else may want to register it.
Crappy domains are regged every single day. Most end up thrown away, never renewed, because owners find out they have crappy domains.
Whenever I see trademark violations, I advise domain owners to delete the domains right away. Others give out the same advice. So that's 1 reason.
I never deleted a domain name, if I lose interest I just leave them to expire, but I can imagine if someone delete a domain name then maybe it could be due to legal issues such as trademark infringement.
I just learned something I just let it expire if it doesn't work, I didn't know I could delete it. Thanks.
They just don't want others to have the same domain name similar to theirs hence many people delete domain names.
Sometimes I realized the domain I bought didn't really reflect my project, so I either sold, deleted or gave away the domain in question, to replace it with a new, more suitable one as soon as possible. Other times I've deleted domains just because of financial issues. But generally speaking, I don't delete domains-- I love them this much.
All the responses are not the main reason why people do that DMCA cease and desist Believe me when you get a notice from the legal department or a private copyright /trademark law firm representing a big player that they are going to sue you because of a domain you own you would be amazed at how fast most domain owners "rethink their priorities" and cower in the corner "please don't sue me sir".. LOL right about that time the idea of plausible deny-ability creeps in and they think "how can I stay out of trouble" right after then is when they hit the drop button ..LOL