What are the advantages and disadvantages of static websites?

Static sites are cheap, fast, and search-friendly, but they cannot do anything interactive and are painful to keep up to date by hand.

A static site is just files on a plain web server, which buys you a lot of simplicity. The flip side is that "just files" also means no logic: nothing can react to a user.

Advantages:

• Simple technologies — only HTML and CSS are strictly required, so the barrier to entry is low.
• Minimal infrastructure — a basic web server is enough; no application runtime or database to operate.
• Search-engine friendly — the finished text is right there in the file, so crawlers index it automatically.
• Fast — no server-side computation per request, so pages come back quickly.

Disadvantages:

• Update and consistency problem — every change means editing files by hand; a shared header copied across 100 pages must be fixed 100 times.
• No application functionality — no search, ordering, or personalization is possible.

Tip: the update pain is the one disadvantage with a clean fix. Static Site Generators (Jekyll, Hugo, Gatsby) let you write content once and templates once, then auto-build all the final HTML — keeping static's speed while removing the manual drudgery.