What is SaaS? Why the World Moved from Discs to Subscriptions

​1. The Old Way vs. The New Way
​In the old days, if you wanted a computer program, you went to a store, bought a physical disc, and installed it. If the company made a better version, you had to buy a new disc.
​SaaS (Software as a Service) changed everything. Now, the software lives on the internet (the Cloud), and you "rent" it every month.
​2. Why Companies Love SaaS
​No Installation: You just log in through your web browser (like Chrome).
​Always New: When the company fixes a bug, it updates for everyone instantly. You never have to "update" manually.
​Pay as You Go: Instead of paying $500 once, you pay $10 a month. This makes it easier for small businesses to start.
​3. Examples You Already Use
​Entertainment: Netflix and Spotify.
​Work: Google Docs and Microsoft 365.
​Business: Shopify (which you used for your brand) and Slack.
​4. The Technical Side: The "Multi-Tenant" Brain
​As an engineer, the coolest part of SaaS is Multi-tenancy. Imagine a giant apartment building. The building (the software) is owned by one company, but many different families (the users) live in their own private rooms. They share the same roof and plumbing, but they can't see into each other's rooms.