When two people are on a date, they are gathering information about each other for further thought. Part of their time together at first will be spent in deep conversation, and they will often start the process with bare facts of where they were born and grew up. These are not all that important for many people, but they help form a base for comparison. Each piece of information gathered will help them move on to the next step.
It can take months before the pair has learned enough about each other to decide on their compatibility for a long term relationship, and it could still not work out. They might have grown up with similar backgrounds, and their goals could be the same. They might have hobbies they share, and they could even have several friends in common. These are all good signs, but there are more ingredients for a great relationship if they want to make it a long term one.