An email address is not just a contact. It is a clue.

Every email address contains structure, provider hints, and sometimes the person's name, handle, or employer.

Parts of an email address

• **Local part** (before @): May contain name, initials, birth year, or a handle.
• **Domain**: Reveals email provider, company, or custom domain.
• **Plus addressing**: Some providers treat "name+tag@domain.com" as the same inbox — useful for tracking who sold your data.

What the domain tells you

• **Gmail / Outlook / Yahoo**: Personal addresses, harder to trace.
• **Company domain**: Likely work address — reveals employer.
• **Custom domain**: Self-hosted or small business. WHOIS the domain for more.
• **Disposable providers** (Mailinator, 10MinuteMail): Likely throwaway, low signal.

Quick email validation

Before investing time investigating an email, check if it exists:

• **Emailhippo** or **Hunter.io**: Verify if the address format is valid.
• **Have I Been Pwned**: Check if the address appears in known breaches (useful for pivoting).
• **Google search** in quotes: See if the address appears on public pages.

An email address that leads to a dead disposable domain is usually not worth the effort. Move on to higher-signal sources.