A professional e-mail address is defined as one that, in its entirety, represents and reflects the professional interests of the user or owner of the e-mail address itself. A professional e-mail address forms a constituent part of how individuals or organisations actively market their products, services, skills, or professional objectives. A professional e-mail address also therefore communicates factual, useful, and meaningful information about the owner or user of the address.

To determine whether an e-mail address is professional, ambiguous, or unprofessional, both parts of the address, i.e. the local element before the ‘@’ sign and the domain name that follows have to be considered. Furthermore both elements have to be judged singularly and jointly to determine whose interests the e-mail address best represents.

To clarify further it is worth looking at examples and classifying them accordingly. For the purpose of examination the examples are based on the premise that the owner is using the e-mail address in a professional context.

Examples and classification

john.doe@companyABC.com
Context: John Doe has a professional relationship with the domain name owner.
In this example the local element before the ‘@’ sign adopts a conventional, informative and factual format, and the domain name represents and promotes the interests of an entity that John Doe has a professional relationship with (namely companyABC).
Class: Professional.

sales@companyABC.com
Context: ‘sales’ has a professional relationship with the domain name owner.
In this example the local element before the ‘@’ sign adopts a conventional, informative and factual format, and the domain name represents and promotes the interests of an entity that ‘sales’ has a professional relationship with (i.e. companyABC).
Class: Professional.

jane.doe@mortgagebrokers-sonline.com
Context: The domain owner has a professional relationship with Jane Doe and others who operate in the mortgage broker industry.
From Jane Doe’s perspective the domain name represents three separate entities: Jane herself, others that use mortgagebrokers-online to market their services, and the entity that operates mortgagebrokers-online itself. In this case separate parties are operating in consensus to share a domain name for mutual advantage The domain name identifies and communicates the industry that Jane is operating in, and the local element before the ‘@’ sign, (i.e. her name), is conventional, informative, and factual.
Class: Professional.

john.doe@it-consultant.com
Context: john.doe is an IT consultant but has no professional relationship with the domain owner.
In this example the local element before the ‘@’ sign is conventional, informative, and factual, and the domain name acts to identify and therefore market John Doe’s skills or services.
Class: Professional.

teddy.bears@myunusual-domain.com
Context: the term ‘teddy.bears’ has a professional relationship with myunusual-domain.com and is relevant to a service, product, or other element associated with the owners’ professional interests.
This e-mail address can initially appear to be unprofessional however the owner may be providing a niche service. From the owner’s perspective the entire e-mail address may accurately reflect their business interests in a meaningful and professional sense.
Class: Professional.

companyABC@yahoo.com
Context: companyABC and yahoo.com have no professional relationship.
In this example the elements before and after the ‘@’ sign adopt a conventional, informative and factual format. Use of this e-mail address virally markets the name of companyABC, however it also endorses the services of the webmail service / domain owner. CompanyABC is using an address that in its’ entirety, does not represent or promote its professional interests. Given the relative ease of acquiring a professional domain name, and the fact that companyABC is claiming an Internet presence, use of this email address is not considered professional.
Class: Ambiguous / unprofessional.

jane.doe@gmail.com
Context: jane.doe and gmail.com have no professional relationship.
As with the previous example this address acts to serve the interests of the domain owner / service provider. Whilst jane.doe has elected to use a standard format for the local element before the ‘@’ sign, the overall e-mail address does not actively market or promote her professional interests.
Class: Unprofessional.

johndoe.superguy06@hotmail.com
Context: johndoe.superguy06 and hotmail.com have no professional relationship. Assuming Johndoe has no professional interest associated with the term ‘superguy06’ this e-mail address does not actively promote or market johndoe in a professional context. Furthermore, the format used before the ‘@’ sign is, for argument purposes, neither factual nor informative and will not be respected professionally. The address does however actively promote the e-mail service provider. Johndoe has endorsed their service and is performing viral marketing on their behalf. From the service providers perspective their professional interests have been represented in a positive manner by the fact that Johndoe is using their product.
Class: Unprofessional.

Conclusion
In order for an e-mail address to be classified as professional, ambiguous, or unprofessional, it needs to be considered in context, format, and in terms of factual and informative content. The local and domain name elements of the address need to be considered in their relationship to each other, and the intended audience of the e-mail address needs to be understood.