Zoom

Sierra

Zoom

Zoom uses a freemium model. Free accounts get unlimited one-on-one meetings and 40-minute group meetings.

Paid plans start at $13.33/month per user for Pro (meetings up to 30 hours), $18.33/month for Business, and custom pricing for Enterprise. Zoom also charges for add-ons — Zoom Phone (cloud phone system), Zoom Rooms (conference room hardware), and Zoom Contact Center.

The free tier is the hook. The 40-minute limit on group calls creates just enough friction to push power users to pay.

And once one person in a company pays, the whole team follows because nobody wants to be the one whose meetings keep getting cut off.

Sierra

Companies pay Sierra to run their customer service with AI agents instead of hiring rooms full of humans. The agent talks to your customers over chat.

It answers questions. It processes returns.

It updates subscriptions. Here is the clever part.

Sierra charges based on outcomes, not seats. Brands pay when the AI actually resolves a problem, not just for having the software installed.

That pricing is unusual. Most software charges a flat monthly fee no matter what.

Sierra only gets paid when the bot does the job.

Zoom

Eric Yuan grew up in Tai'an, a mining city in Shandong province, China. In the mid-1990s he was in his twenties and inspired by the internet boom happening in America.

He applied for a US visa. He was rejected.

He applied again. Rejected again.

Eight times in total over about two years before he was finally approved in 1997. He moved to Silicon Valley with barely any English and joined WebEx as one of its first engineers.

Yuan spent 14 years at WebEx, eventually becoming VP of Engineering. Cisco acquired WebEx in 2007 for $3.2 billion.

Yuan watched Cisco slowly bloat the product with enterprise features while the core video quality deteriorated. He kept telling Cisco leadership they needed to rebuild the product from scratch.

They kept saying no.

In 2011, Yuan quit and took 40 WebEx engineers with him. He founded Zoom Video Communications with a simple thesis: video meetings should just work.

No downloads. No lag.

No "can you hear me?" No IT department required. He built the product that Cisco refused to build.

Sierra

Bret Taylor had already done the impossible twice. He co-created Google Maps.

He later became co-CEO of Salesforce, chaired Twitter's board during the messy Elon Musk takeover, and became chairman of OpenAI in late 2023. Clay Bavor spent 18 years at Google, most recently running its Labs group.

The two friends left their big jobs in 2023 to build something together. They picked customer service on purpose.

It is the least glamorous corner of software. Their logic was simple.

Companies hate their support costs. Customers hate waiting on hold.

AI that actually resolves problems could fix both sides at once. They launched Sierra in February 2024 with $110 million from Sequoia and Benchmark.

Zoom

Zoom grew on one thing: it worked. In a world where every video call started with five minutes of technical issues, Zoom calls just connected.

That reliability was the entire marketing strategy for the first five years.

The freemium model did the rest. Teachers, coaches, therapists, book clubs, and small teams all started on the free tier.

When they hit the 40-minute limit, enough of them converted to paid. And every free meeting was essentially a demo — everyone in the meeting saw how good Zoom was.

Yuan obsessed over simplicity. While competitors like WebEx and GoToMeeting required downloads, plugins, and IT involvement, Zoom worked in the browser with one click.

The learning curve was essentially zero. Your grandmother could figure it out.

That turned out to be extremely important when a pandemic suddenly required your grandmother to figure it out.

Then COVID happened. In March 2020, the world shut down.

Every meeting — work, school, family, doctor, church, happy hour — moved to video. Zoom was already the easiest option.

Daily participants exploded from 10 million to 300 million in four months. The stock went from $70 to $588.

Sierra

Sierra went straight for big brands, not tiny startups. SoFi, Ramp, ADT, Sonos and Brex signed up early.

By 2026 it said more than 40% of the Fortune 50 were customers. The trick was trust.

Enterprises are terrified of an AI bot going rogue and insulting a customer. So Sierra built guardrails and let each company control exactly how the agent behaves.

Bret Taylor's contacts did the rest. When the chairman of OpenAI calls a Fortune 500 CEO, they pick up.

Sierra hit $100 million in annual recurring revenue in November 2025, seven quarters after launch, and $150 million by February 2026. In April 2026 it launched Ghostwriter, which builds and deploys a new agent from a plain-English description.

Zoom

The post-pandemic hangover has been severe. Zoom's stock peaked at $588 in October 2020 and crashed to under $70 by 2022 — an 88% drop.

The company went from the most exciting tech stock on the planet to a cautionary tale about pandemic valuations. Revenue growth slowed from 300%+ to single digits as people returned to offices and competitors caught up.

Security and "Zoombombing" were early crises. In early 2020, as millions of new users flooded in, trolls discovered they could join open Zoom meetings and share offensive content.

Schools, churches, and AA meetings were disrupted. It turned out Zoom's encryption wasn't truly end-to-end as advertised.

Yuan had to halt all feature development for 90 days and focus exclusively on security fixes. It was a near-death reputational crisis.

Competition from Microsoft Teams and Google Meet intensified. Both companies bundled video calling for free into products that hundreds of millions of people already used.

Microsoft Teams integrated directly into Office 365. Google Meet was built into Gmail.

Zoom had to compete against free products from two of the richest companies on Earth.

Sierra

Everyone is building AI customer service agents right now. Decagon has raised at a multi-billion valuation.

Salesforce, ServiceNow and Intercom all shipped their own agents. Sierra is not the cheap option.

It sells premium AI to giant companies that move slowly. The bigger risk sits underneath the product.

Sierra does not make its own AI models. It rents them from providers like OpenAI and Anthropic.

If those model makers decide to compete directly, Sierra's edge gets thin fast, and its co-founder chairing one of them only makes that question louder. A $15.8 billion valuation on roughly $150 million in revenue leaves almost no room for a stumble.

Zoom

Zoom Meetings is the core — video calls that actually work. Zoom Webinars handles large-scale events with up to 50,000 attendees.

Zoom Phone is a full cloud-based phone system replacing traditional office phones. Zoom Rooms turns physical conference rooms into one-click video meeting spaces.

Zoom Contact Center competes with established call center software. Zoom Team Chat is their Slack/Teams competitor.

Zoom Whiteboard is a collaborative digital canvas. Zoom Revenue Accelerator uses AI to analyze sales calls.

And Zoom AI Companion summarizes meetings and drafts messages.

Sierra

The core product is the Sierra AI agent. It is a branded customer service bot that companies deploy on their website, app, and phone lines.

It handles the boring stuff. Order tracking.

Refunds. Password resets.

Account changes. Sierra also built its own tools to test and monitor these agents so they do not make things up.

In 2024 the company added a voice version that talks to customers on the phone. In April 2026 it added Ghostwriter, a tool that builds and deploys a new agent from a plain-English description.

The whole pitch is one AI agent that carries your brand's name and never sleeps.

Zoom

Sequoia Capital, Emergence Capital, Horizons Ventures (Li Ka-shing), Qualcomm Ventures

Sierra

Sequoia Capital and Benchmark wrote the first checks at launch in February 2024, $110 million between them. Greenoaks Capital then led both the $175 million round in 2024 and the $350 million round in September 2025.

In May 2026 Tiger Global and Google's GV led a $950 million round at a $15.8 billion valuation, with Benchmark, Sequoia and Greenoaks back in. That takes total funding to about $1.6 billion.

That is partly the product and partly Bret Taylor. Investors bet on founders who have already built billion-dollar things.