Hmm. I normally don't use the term, because I consider it inaccurate, but I'm not sure how it's derogatory. Maybe you can tell me how it is.
Generally I use the term "developing nation". In this case, I think I wrote "Third World" because it's meant to be ironic - people see it as undesirable but I find it amazing. Maybe that's what you meant when you said it's derogatory.
Anyway, I'm not likely to use the term again soon.
Thanks for your comment