Stephanie Brown definitely had one of the more interesting introductions into the Batman team. As she was first Tim Drake's girlfriend, who was then hired by Batman to be his Robin (one of the only females to be that). But...it was all in an attempt to get Tim Drake back as Robin, she didn't appreciate that. So, she became the hero known as Spoiler.
After that though, she had a long tenure as Batgirl, one she stayed at for quite some time until the New 52, where she returned to her Spoiler role.
Stephanie is smart, and knows how to use computers just as well as anyone. She even found a way to use Twitter to locate where Batman was so that he could help her. Despite being drafted under the wrong circumstances, she's proven herself valuable time and time again.