Basically, she was being a bitch, but she was not a threat to the police in any way. They had absolutely no reason to resort to a taser as quickly as they did. She should (and probably will) sue the police, and if I was on the jury -- based on the vid -- I'd vote in her favor.
Cops are too eager to use the tasers, and people are dying because of it (happened again just last week in Ohio, guy got tasered, ends up dead). If a taser has the potential of killing someone, then you must justify the use of (potentially) deadly force when using a taser. More and more lawsuits will be filed until the cops either get better training in how and when to use the tasers, or the tasers get outlawed.