Summary
The financial burden of spam and email delivery is distributed across multiple parties: senders, recipients, mailbox providers (like Gmail), and ISPs. Senders cover the costs associated with initial email transmission up to the SMTP transaction, including bandwidth and infrastructure. Recipients, through their ISPs and resources, incur indirect costs related to hardware, electricity, and time spent managing their inboxes, including dealing with spam. Mailbox providers invest heavily in infrastructure for storage, filtering, and security. Some costs, such as spam filtering technologies, disproportionately affect recipients. Though spammers often use stolen resources, making their immediate sending costs negligible, legitimate senders still pay for email marketing platforms and associated development. SMTP's design enables cost-sharing among participating systems, and recipients bear more cost of email delivery these days.
Key findings
- Shared Cost Burden: Costs are spread across senders, recipients, mailbox providers, and ISPs.
- Sender SMTP Costs: Senders pay initial transmission costs up to the SMTP transaction.
- Recipient Indirect Costs: Recipients bear indirect costs through ISP fees, hardware, electricity, and time spent managing spam.
- Provider Infrastructure Investments: Mailbox providers invest in infrastructure for storage, filtering, and security.
- Spammer Reduced Costs: Spammers using stolen resources have reduced direct sending costs.
- Legitimate Sender Platform Costs: Legitimate senders pay for email marketing platforms and development.
- Increased recipient costs: Receivers bear a lot more of the cost of mail delivery these days.
Key considerations
- Cost Distribution Dynamics: Cost distribution shifts with technology, spam tactics, and filtering efficiency.
- Definition of 'Cost': Consider all resources, not just direct financial outlays (e.g., time, bandwidth).
- SMTP Store and Forward Process: SMTP's architecture allows for sharing costs across many systems.
- True Cost of Free Services: Free services are often subsidized by data monetization or advertising, a cost to users.
- Opt-in Validity: Data quality varies, and claimed opt-in status may not be legitimate, influencing effectiveness and cost.
What email marketers say
7 marketer opinions
The cost of spam and email delivery is shared between senders, recipients, and email providers. Senders bear costs related to creating, sending, and infrastructure (e.g., email marketing platforms). Recipients indirectly pay through ISP fees, hardware/electricity usage, and the time spent managing their inbox and deleting spam. Email providers invest in infrastructure for sorting, filtering, and storing emails, costs which are often passed onto users through subscriptions or indirectly via data monetization.
Key opinions
- Shared Cost: The financial burden isn't solely on one party; it's distributed among senders, recipients, and email providers.
- Sender Costs: Senders pay for creating and sending emails, email platforms, and infrastructure.
- Recipient Costs: Recipients incur costs through ISP fees, hardware usage, electricity, and time spent managing their inbox (e.g., deleting spam).
- Provider Investment: Email providers invest in infrastructure for receiving, filtering, and storing emails, with costs passed on to users.
Key considerations
- Indirect Costs: Recipients' costs are often indirect and less obvious (e.g., electricity, time spent deleting spam) but still contribute to the overall expense.
- Provider Monetization: Email providers may monetize user data to offset the cost of providing free email services.
- Evolving Costs: The distribution of costs may shift over time as technology evolves and spam filtering techniques improve.
Marketer view
Email marketer from Mailjet states that senders pay for the cost of sending emails, including infrastructure, software, and personnel. Recipients pay indirectly through their internet service provider (ISP) fees and the time spent managing their inbox, including deleting spam.
19 Jan 2025 - Mailjet
Marketer view
Email marketer from EmailToolTester shares that email providers invest in infrastructure to receive, sort, filter, and store emails, leading to costs. The user then pays for this through their subscription or indirectly via data usage.
19 Jan 2025 - EmailToolTester
What the experts say
7 expert opinions
The cost of spam and email delivery is complex and shared between senders, recipients, and mailbox providers. Senders pay for the initial transit up to the SMTP transaction. After that, the recipient's system incurs the costs, including spam filtering and storage. While 'true' spammers may operate with virtually zero sending costs by using stolen resources, legitimate senders still pay. Additionally, recipients bear a significant portion of spam-related costs through filtering technologies and infrastructure. There are experts who have been offered substantial sums to help spammers improve delivery, indicating spammers are willing to pay for effective strategies.
Key opinions
- Shared Responsibility: The cost isn't solely borne by one party; senders, recipients, and mailbox providers all contribute.
- Sender's SMTP Cost: Senders are responsible for transit costs up to the SMTP transaction.
- Recipient's System Cost: Beyond the SMTP transaction, the recipient's system incurs costs like spam filtering and storage.
- Spammer Tactics: True spammers minimize costs by using stolen resources, making their direct sending costs minimal.
- Filtering Costs: Recipients bear considerable expenses related to spam filtering infrastructure.
- Spammer Investment: Spammers are sometimes willing to invest significantly to improve email delivery.
Key considerations
- Cost Distribution Shifts: The relative burden on senders and recipients can vary based on technological advancements (e.g., filtering effectiveness) and spam tactics.
- Definition of 'Cost': Cost includes not only financial expenses (e.g., infrastructure, subscriptions) but also resources such as time and network bandwidth.
- Ethical Considerations: The willingness of some to assist spammers, despite the harm they cause, raises ethical questions.
Expert view
Expert from Email Geeks shares that spammers will absolutely pay for things and recounts experiences working with and being approached by spammers.
7 Jun 2023 - Email Geeks
Expert view
Expert from Email Geeks explains that the cost of spam is carried by the recipient network not the senders, while the cost of postal mail is carried by the sender completely. True spam is sent from stolen resources so the sending cost is virtually zero. Spam filtering and message storage is expensive for your mailbox provider and is multiplied by the number of users on the platform.
27 Nov 2023 - Email Geeks
What the documentation says
4 technical articles
The cost of spam and email delivery is distributed across senders, recipients' mail servers/ISPs, and email providers. Senders bear the initial transmission costs until the recipient's server accepts the message. Recipients' mail servers and ISPs incur the expenses of spam filtering, including software, hardware, and personnel. Email providers, such as Gmail, are responsible for email storage costs, encompassing data centers and infrastructure. SMTP's store-and-forward process enables cost sharing across multiple systems involved in message delivery.
Key findings
- Sender Transmission Costs: SMTP senders pay for the initial email transmission.
- Recipient Filtering Costs: Recipient mail servers and ISPs pay for spam filtering infrastructure and resources.
- Provider Storage Costs: Email providers are responsible for the cost of storing emails.
- Shared Infrastructure: SMTP's architecture facilitates cost sharing among multiple systems.
Key considerations
- Filtering Efficiency: The efficiency of spam filtering directly impacts the costs borne by recipients and email providers.
- Scalability: As email volume increases, the costs associated with storage and filtering also rise, necessitating scalable infrastructure.
- Technology Evolution: Advancements in SMTP and spam filtering technologies continually influence cost distribution.
Technical article
Documentation from ietf.org explains that the SMTP sender pays for the initial transmission of the email, up until the message is accepted by the recipient's mail server. This includes the cost of bandwidth and resources used to send the email.
6 Jun 2022 - ietf.org
Technical article
Documentation from support.google.com explains that the recipient's email provider (e.g., Gmail) bears the cost of storing emails. This includes the cost of data centers, servers, and other infrastructure required to store and manage user inboxes.
17 Aug 2024 - support.google.com
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