How can PHP developers leverage insights from large-scale social networking platforms like Facebook to improve the efficiency and effectiveness of storing and retrieving user interactions and content in their own projects?

To improve the efficiency and effectiveness of storing and retrieving user interactions and content in PHP projects, developers can leverage insights from large-scale social networking platforms like Facebook by implementing a database structure that efficiently stores and retrieves data, optimizing queries for faster retrieval, and utilizing caching mechanisms to reduce server load.

// Example of optimizing queries for faster retrieval using indexing
// Create an index on the 'user_id' column in the 'interactions' table
$query = "CREATE INDEX user_id_index ON interactions (user_id)";
mysqli_query($connection, $query);