AI Explained Plainly home

Guide · · 5 min read

What is generative AI? A plain-English explanation

LeadersProfessionalsService & Veterans

Want one workflow like this by email each Tuesday? It's free. Get it below

You've probably heard "GenAI" in three meetings this month and nodded along. That's fine. The idea underneath it is simpler than the buzz makes it sound, and once you get it, you'll have a much better feel for when to trust these tools and when not to.

The short version

Generative AI is software that creates something new (a paragraph, an image, a summary, a line of code) when you ask it in plain language. ChatGPT, Claude, Gemini, and Microsoft Copilot are all generative AI tools.

The "generative" part is the point. Older software mostly sorted, searched, or calculated things that already existed. This kind writes a fresh answer every time you ask.

How it actually works (no math)

Think about the autocomplete on your phone. You type "running late, be there in" and it suggests "10 minutes." It's guessing the next word based on what usually comes next.

Generative AI is that same basic idea, scaled up enormously. The text versions are built on what's called a large language model, or LLM. "Large" because it learned from a massive amount of text. "Language model" because what it learned is how language tends to fit together.

When you ask it a question, it isn't looking up a stored answer. It's building a response one small piece at a time, each time picking what's most likely to come next given your question and everything it's written so far. That's why the same question can get a slightly different answer twice.

Image tools work on a similar principle with pictures instead of words. They learned what images tend to look like and generate a new one that fits your description. Voice tools do the same with sound, which is why AI voice cloning scams can now copy someone's voice from a short clip.

Why it sounds so confident (and why that's a problem)

Here's the part most people miss. Because the model is predicting likely-sounding text, it can produce something that sounds completely right and isn't. A made-up date. A quote nobody said. A source that doesn't exist.

This is usually called a hallucination. OpenAI's own help center says ChatGPT can sound confident even when it's wrong, and that it can produce fabricated quotes, studies, and citations. Their advice is to treat it as a first draft, not a final source.

Many tools can now search the web and show links, which helps. But a link isn't proof. Click it and check that it says what the AI claims.

What it's genuinely good at

In my view, generative AI earns its keep on jobs where you already know what right looks like and just want a faster first pass:

  • Turning messy notes into a clean summary or action list
  • Drafting an email you'd otherwise stare at for 15 minutes
  • Rewording something to be shorter, friendlier, or more formal
  • Explaining a dense document or term in plain language
  • Brainstorming options you can then pick from

Notice the pattern. You stay the judge. The AI does the typing.

If you want to try one of these right now, our guide to writing a professional email with AI has copy-paste prompts, and Issue #1 walks through turning meeting notes into an action list.

What it's bad at

It's weak at anything where being wrong is expensive and you can't easily check the answer. Legal conclusions, medical advice, exact numbers, and current facts all need a real source behind them.

It also doesn't know your situation unless you tell it. It doesn't know your client, your boss's preferences, or what happened in last week's meeting. That's why the context you give it matters so much, and it's also why people end up pasting things they shouldn't.

What not to paste

The rule we use everywhere on this site: if you wouldn't email it to a stranger, don't paste it into a free AI tool.

That covers customer names and contact details, Social Security numbers, health information, passwords, account numbers, unreleased financials, and anything your employer marks confidential. If your company gives you an approved work AI tool, use that one for work and follow its policy.

If you serve, the bar is higher. Never paste classified information, CUI (Controlled Unclassified Information, the "sensitive but not classified" category), personal data, or unit and operational details into a commercial AI tool. The Service Members & Veterans track covers the approved options.

AI Explained Plainly is not affiliated with, approved, or endorsed by the Department of Defense/Department of War, any military service, or the VA.

Issue #1 shows exactly which setting to change in ChatGPT, Gemini, Copilot, and Claude so your chats aren't used for training.

Generative AI vs. "regular" AI

You'll hear both terms, so here's the quick difference. "AI" is the big umbrella. It includes things like spam filters, fraud detection, and the system that recommends your next show. Those mostly classify or predict.

Generative AI is the slice that creates content. When someone at work says "we should be using AI," they almost always mean this slice, usually a chat tool.

You'll also hear about AI agents, which take actions instead of just answering. They're built on the same kind of model, with tools attached.

Which tool should you start with?

Honestly, for learning what this stuff can do, the free version of almost any major tool is enough. If your company already pays for one (Copilot inside Microsoft 365, or Gemini inside Google Workspace, for example), start there, since it's the one you're allowed to use with work information. And if you're wondering whether the paid ChatGPT plan is worth it, most people learning the basics don't need it yet.

If you're choosing on your own, our ChatGPT vs. Claude vs. Gemini vs. Copilot comparison breaks down who each one fits, with prices checked against the vendors' own pages.

Try this today

Pick one low-stakes thing you wrote this week, something with no names or private details. Paste it into a free AI tool with this:

Rewrite this so it's shorter and easier to read.
Keep my meaning. Don't add any facts I didn't include.
Then list anything you changed that I should double-check.

[paste your text here]

Read what comes back with a skeptical eye. That one exercise will teach you more about how generative AI behaves than any explainer, this one included.

Sources