❓ Problem

Email never solved spam, it just got better at hiding it. Kaspersky found that 44.99% of global email traffic was spam in 2025, almost every second message. Most of it gets caught. What slips through is the new problem: the authenticated, polite, relentless cold pitch from a real person at a real company.

AI made that pitch free to write, and software made it free to send. Instantly, a cold outreach platform, has grown to an estimated $38.2M in revenue without raising a cent of outside funding. The sending side is a booming industry. The receiving side gets a block button.

And blocking changes nothing beyond your own inbox. The average cold email response rate sits at about 0.7%, so senders already budget for 99 out of 100 people to ignore or block them. Your block is priced in. The sender moves on to the next founder, and everything you learned about that sequence dies with you.

The kicker: inbox providers already decide who lives and dies on complaint data. When Google and Yahoo set a 0.3% spam complaint threshold, the average B2B complaint rate was 2.01%, almost seven times over the limit. Complaints are the currency. Individuals just have no way to pool theirs.

✅ Solution

Penny Spam, a shared spam blacklist with a Gmail and Outlook extension, where every report costs one cent.

• Report in one click, for a penny. When an unwanted email lands, hit the Penny Spam button to submit the sender and the offending message for review. Users preload a small balance ($1 buys 100 reports), so there’s no checkout every time and card fees don’t swallow the penny.
• A reputation score built from independent reports. Each sender is scored on the number of unconnected reporters, the evidence attached (the full sequence, the fourth “just bumping this”) and repeat behaviour across domains. One angry person can’t sink anyone. Fifty unrelated founders reporting the same sequence can.
• Opt-in filtering with dials. Users choose how aggressive to be: filter confirmed offenders only, or switch on a stricter “persistent cold pitch” mode that catches senders on their third follow-up.
• A fair appeals process. Flagged senders can see the flag and challenge it with context, so a legitimate business isn’t blocked for everyone over one bad day.

The wedge is founders drowning in sales outreach. Underneath sits a person-level reputation network for cold email, data that email-security tools and inbox providers don’t currently have.

📊 Key Numbers

Market size

• The email security market was worth $5.46 billion in 2025 and is projected to hit $14.44 billion by 2034. That’s the TAM.
• SAM is the slice spent on reputation data and prosumer inbox filtering. Assuming 5-10% of the market, that’s a $300-500M pool (our estimate).
• People already pay for inbox sanity alone: SaneBox charges $7 to $36 a month with no network effect whatsoever.

ARR potential

• The pennies aren’t the business. 20,000 active reporters filing 40 reports a month is about $8,000 a month. The cent is a spam filter for the spam filter.
• Bottom-up: 25,000 Pro users at $6/mo for filtering is $1.8M ARR. 1,000 teams at 20 seats and $5/seat adds $1.2M. 30 email-security and sales-tool customers licensing the reputation feed at $75,000 a year adds $2.25M. That’s a ~$5M ARR business within a few years.