ProgrammerGirl questions

• Adding a Forum to my site: build one from scratch or use existing open-source platform? [closed]
• Which Composite Index would make this simple MySQL query faster?
• What Cache Headers should you use on your PHP site with CloudFlare so that "Always Online" works?
• How to check Cookie Token against bcrypt-hashed Token in DB when using Persistent Login Cookies?
• How to SELECT two columns, where one column must be DISTINCT?
• What is the fastest and most efficient way of storing and fetching images when you have millions of users on a LAMP server?
• How to convert Emojis to their respective HTML code entities in PHP 5.3?
• Which implementation of bcrypt is recommended for PHP 5.3?
• How to store Birthdate and Age so that Age can be updated daily in PHP/MySQL?
• How to continuously keep the number of bcrypt rounds relevant to the current year's hardware?

ProgrammerGirl answers