There are several technology stacks that can be used to build a website to collect user data for machine learning. Some popular options include:

- **MERN stack**: This stack consists of MongoDB, Express.js, React.js, and Node.js. It is a popular choice for building fast and scalable web applications using JavaScript. MongoDB is a NoSQL database that allows the handling of documents for your website. It allows developers to create databases, schemas, and tables to handle different types of databases for their websites⁷.

- **MEAN stack**: This stack consists of MongoDB, Express.js, Angular.js, and Node.js. Like the MERN stack, it is also a popular choice for building fast and scalable web applications using JavaScript.

- **LAMP stack**: This stack consists of Linux, Apache, MySQL, and PHP. It is a popular choice for building dynamic web applications using PHP.

Each of these stacks has its own pros and cons. For example, the MERN and MEAN stacks are popular choices for building fast and scalable web applications using JavaScript, while the LAMP stack is a popular choice for building dynamic web applications using PHP.

It's important to choose a technology stack that best fit your needs and skillset. Is there anything else you would like to know?
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