Header 
Header
The header in an email is the part of the email that is not transparent to the recipient unless they have their "View Headers" option turned on. This tells the recipient what servers the email is coming from and what programs are being used to generate this email. Headers contain detailed information on the email itself and the route it's taken across the Internet. Recipients can normally see the "to" (identity of recipient), "from" (identity of sender) and "subject" headers in their inbox.
- A/B Split
- Above-The-Fold
- ASP
- Auto Reply
- Auto Responder
- B2B
- B2C
- Bandwidth
- Blacklist
- Bounce (Hard)
- Bounce (Soft)
- Call To Action
- Campaign
- Can-Spam Act of 2003
- CAPTCHA
- Challenge Response
- Click-Through Rate (CTR)
- Content
- Conversion Rate
- Cost Per Thousand (CPM)
- Database
- Dedupe
- Domain Key / DKIM
- Double Opt-In
- Email Blocking
- Email Client
- Email Newsletter
- Email Service Provider
- eZine
- False Positive
- Font
- From/Sender Address
- From/Sender Name
- Harvesting
- Header
- HTML Email
- IP Address
- ISP
- Landing Page
- Links
- Load Time
- Mailing List
- Multi-Part MIME Email
- Open Rate
- Open Relay
- Opt-In Subscriber
- Opt-Out List
- Opt-Out Subscriber
- Permission Based Email
- Personalization
- Phishing
- Preview Pane
- Privacy Policy
- Rental List
- Segmentation
- Signature
- Single Opt-In
- Spam / UCE
- Spam Trap
- SPF Record
- Spoofing
- Subject Line
- Targeting
- Unique Selling Proposition
- Unsubscribe
- URL
- Viral Marketing
- Web-Friendly Fonts
- Whitelist
