In many Austin and Ally fanfictions where Austin kisses Ally, it often represents a significant moment in their relationship development. It could be a culmination of their long - hidden feelings for each other. For example, in some fanfictions, this kiss might happen after a big performance where they realize how much they mean to one another. It's a moment that fans love to read about as it shows the deepening of their bond.
As the name is not widely known in a common 'love story' context, it could be an individual with a personal story. Maybe Ally McGraw is just an ordinary person who has an extraordinary love story to tell, perhaps someone from a small community or a specific social circle.