You are spot on! Using how someone signs off as an indicator on how to address them moving forward is appropriate and acceptable. And if you’ve met someone in person and they were introduced by their first name — that too is an additional indicator as well.

Keep in mind many folks use the same formal signature file for all their e-mails when they should also have a sig file for those communications that do not require they sign off with “firstname lastname”.

I talk about this in Signature Files Dos and Don’ts.

I also have a Business E-mail Etiquette site that talk about only business e-mail issues if you are interested: BusinessEmailEtiquette.com

Thanks for stopping by! ;-)