Sam is possessed by what is believed to be a Goa'uld, but is really a Tok'ra. I thought this was a great way to introduce a new alien species. We didn't learn a whole lot about the Tok'ra in this episode, but they will be very important in the years to come.
Although, from what I know now about the Tok'ra, I find it odd that Jolinar would have such an attitude problem. Maybe they think they are better than the Tauri, but she was acting more like a Goa'uld that a Tok'ra.
Not only that, but I would of figured that Teal'c would have been able to figure out who the Goa'uld was on base. Doesn't he have the ability to tell if someone is a gould or not?!?
Well no matter, it was still a great episode and I enjoyed watching it again!