The Inbox Index
The table
Three dimensions, 0 to 4 each: Cadence (does it keep its own rhythm), Volume (how much it sends) and Sales pressure (how often it is selling rather than telling). The grade is the Siftbox Score, out of 12.
| Newsletter | Welcome week | Cadence sends on rhythm | Volume emails / week | Sales pressure sends selling | Siftbox Score out of 12 | |
|---|---|---|---|---|---|---|
| 1 | Healthline: Wellness Wire Health & Wellness | 4 | 100% | 1.4/wk | 0% | 12 Subscriber-first |
| 2 | TLDR Data Technology & Science | 2 | 94% | 1.9/wk | 0% | 12 Subscriber-first |
| 3 | TLDR Product Technology & Science | 2 | 100% | 2/wk | 0% | 11 Subscriber-first |
| 4 | Nomadic Matt Travel & Destinations | 4 | 67% | 1.4/wk | 0% | 10 Attention-first |
| 5 | The Amateur Gourmet Food & Cooking | 3 | 67% | 1.5/wk | 0% | 10 Attention-first |
| 6 | Embedded Technology & Science | 4 | 79% | 2.8/wk | 0% | 10 Attention-first |
| 7 | TLDR Founders Technology & Science | 3 | 97% | 3/wk | 7% | 10 Attention-first |
| 8 | TLDR AI Technology & Science | 5 | 80% | 4.9/wk | 0% | 10 Attention-first |
| 9 | TLDR Design Technology & Science | 5 | 80% | 4.9/wk | 0% | 10 Attention-first |
| 10 | CBC Newsletters News & Politics | 7 | 82% | 5/wk | 0% | 10 Attention-first |
| 11 | TSN Sports | 7 | 100% | 7/wk | 0% | 10 Attention-first |
| 12 | Vogue Runway Fashion & Style | 1 | 65% | 2.4/wk | 0% | 9 Attention-first |
| 13 | Vogue Beauty Fashion & Style | 3 | 73% | 2.6/wk | 0% | 9 Attention-first |
| 14 | The Verge News & Politics | 7 | 79% | 4.8/wk | 7% | 9 Attention-first |
| 15 | Axios Markets Finance & Investing | 5 | 79% | 4.9/wk | 2% | 9 Attention-first |
| 16 | TLDR Marketing Technology & Science | 5 | 80% | 4.9/wk | 2% | 9 Attention-first |
| 17 | Axios Macro Finance & Investing | 6 | 80% | 5.1/wk | 0% | 9 Attention-first |
| 18 | Now Toronto News & Politics | 6 | 90% | 7.4/wk | 1% | 9 Attention-first |
| 19 | Vogue Shopping Fashion & Style | 8 | 91% | 7.6/wk | 1% | 9 Attention-first |
| 20 | Platformer News & Politics | 3 | 31% | 1.6/wk | 0% | 8 Compliance-first |
| 21 | Axios Closer Finance & Investing | 6 | 80% | 5.1/wk | 5% | 8 Compliance-first |
| 22 | Eater Food & Cooking | 9 | 70% | 5.7/wk | 0% | 8 Compliance-first |
| 23 | The Hustle Business & Entrepreneurship | 6 | 68% | 6.1/wk | 0% | 8 Compliance-first |
| 24 | Vogue Fashion & Style | 5 | 64% | 5.6/wk | 2% | 7 Compliance-first |
| 25 | TLDR Technology & Science | 5 | 70% | 5.7/wk | 3% | 7 Compliance-first |
| 26 | NYT Wirecutter Shopping & Reviews | 8 | 98% | 7.1/wk | 30% | 7 Compliance-first |
| 27 | The Points Guy Travel & Destinations | 8 | 98% | 7.1/wk | 19% | 7 Compliance-first |
| 28 | theSkimm Culture & Society | 4 | 54% | 0.8/wk | 19% | 6 Compliance-first |
| 29 | Skimm Shopping Shopping & Reviews | 3 | 67% | 2.1/wk | 20% | 6 Compliance-first |
| 30 | The Daily Skimm Culture & Society | 8 | 87% | 7.8/wk | 19% | 5 Compliance-first |
| 31 | Axios Daily Essentials News & Politics | 17 | 48% | 14.7/wk | 0% | 5 Compliance-first |
| 32 | Front Office Sports Sports | 13 | 51% | 13.7/wk | 8% | 3 Volume-first |
Welcome week counts the emails sent in the seven days after a subscription's first one — the burst the rate calculation sets aside, published rather than hidden. A ▲ marks a welcome week at least half again the edition median of 5. Emails per week is per subscriber, measured over days actually subscribed with the welcome week set aside.
The weeklies
For a publisher, under twelve emails in a window usually just means a weekly. Rhythm cannot be inferred from a handful of sends, so these are scored on Volume alone and graduate to the full table at twelve.
| Newsletter | Welcome week | Emails | Volume emails / week | Weeks observed |
|---|---|---|---|---|
| Esther Perel Relationships & Dating | 6 | 1 | 0.1/wk | ~9 |
| Heather Cowper Travel & Destinations | 2 | 1 | 0.1/wk | ~9 |
| Axios Intelligence News & Politics | 1 | 1 | 0.1/wk | ~8 |
| Tuned In Sports | 2 | 1 | 0.1/wk | ~8 |
| Now Health & Wellness | 3 | 2 | 0.2/wk | ~9 |
| Stephanie Wu, Eater Food & Cooking | 1 | 4 | 0.5/wk | ~9 |
| Lukas Volger Food & Cooking | 1 | 7 | 0.8/wk | ~9 |
| Time Out Travel & Destinations | 1 | 7 | 0.8/wk | ~9 |
| Vogue Business Media | 2 | 7 | 0.9/wk | ~8 |
| the smitten kitchen digest Food & Cooking | 3 | 9 | 1/wk | ~9 |
| Wealthsimple Finance & Investing | 1 | 10 | 1.1/wk | ~9 |
| Vogue Nostalgia Fashion & Style | 1 | 9 | 1.1/wk | ~9 |
| Axios Media Trends Media | 2 | 6 | 1.4/wk | ~4 |
How the index is made
Siftbox sells a solution to the problem this index measures.
The index is free, brands are never contacted before publication, and no brand is ever offered a way to change a score. Scores compare within an edition, not across editions: the Retail Edition measures different dimensions on the same scale. Past editions are never restated.
The panel. Siftbox operates a panel of subscriber inboxes that sign up the way any reader would: an email form on the publisher's own site, no account created, no terms assented to. Every claim traces to a specific email the panel received.
Eligibility. One uniform window for every newsletter. Volume is scored from any live subscription with enough steady-state runway; the other two dimensions additionally require twelve received emails, since a thin sample genuinely misleads. Scoring begins seven days after each subscription's first email, so no newsletter is judged on its welcome series. A subscription that stops receiving mail partway through the quarter is scored up to its last email, so a sender that stopped writing is not mistaken for a restrained one.