Rich snippets (which Google now more often calls rich results) are ordinary search listings dressed up with extra visual detail — star ratings, prices, images, cook times, or event dates — drawn from structured data in a page's HTML. They help a result stand out and can lift click-through, though Google never guarantees they will show.
A rich snippet is not something you write into your title tag. It is generated when Google reads machine-readable markup on the page, matches it to a supported type, and decides the page is eligible. That markup is usually schema.org vocabulary written in JSON-LD, Google's preferred format. Add a Product block with price and an AggregateRating, and your listing becomes eligible to display a price and a row of stars.
Two things trip people up. First, eligibility is not display — Google shows rich results only when it judges them helpful and trustworthy, so correct markup can still yield a plain listing. Second, rich snippets do not directly raise rankings; their value is a fatter, more clickable listing. Implementing and validating this markup sits squarely in technical SEO, and the right test is Google's Rich Results Test before you ever check Search Console.
Take a mid-size online retailer with a page for a $79 espresso grinder. The listing was plain text and earning roughly a 3% click-through rate from position 4. After adding valid Product and AggregateRating JSON-LD, the SERP entry began showing "$79.00 · In stock · 4.6 ★ (212)". Within a few weeks the same position pulled closer to a 5% CTR — the ranking never moved, but the richer listing simply won more of the clicks that were already available.
No. A rich snippet enhances your own normal listing with structured-data extras. A featured snippet is a separate answer box at the top of results that quotes a page to answer a query directly. Different features, different triggers.
Usually a markup error flagged in Search Console, a manual structured-data action for policy violations, or Google simply choosing not to display them for that query. Re-validate the page and confirm the visible content still matches the marked-up data.