One server, many tenants
Think of an apartment building: everyone gets a door, nobody owns the plumbing. On a shared host, the provider runs one web server stack — typically Linux, a web server, PHP and a database — and gives each customer a walled-off slice of the file system plus a control panel. You never see the operating system, and that is the point: updates, security patches and server configuration are the provider's job, not yours.
- What you manage — your site's files, its database content, domains and email addresses, usually through a panel like cPanel or Plesk.
- What the provider manages — the machine itself: OS, web-server software, PHP versions, network, hardware failures.
- What nobody promises — consistent performance. Resources are pooled, so a traffic spike or badly-written script in the next account over can affect your response times.
The economics explain both the price and the limits. Hundreds of small sites fit on one machine, so plans cost less per month than a lunch — and providers enforce soft caps (CPU seconds, concurrent processes, inode counts) that only surface once a site gets popular. That moment, not the price tag, is when people move to a VPS or managed hosting.