Even though this was only the second episode of the year (or second half of the season) HIMYM is moving along at quite a pace. Such a pace that it really doesn;t seem like they;re gonna have enough left for another year.
The momentous thing this episode was that it extinguished one of the more common theories as to who The Mother is.
I, like many fans, thought that the mother was going to end up being Barney's half-sister. This came about when Barney first met his biological father who told him in addition to his son who shares his namesake, he also has a daughter Carly who;s in college. This, combined with the fact that we knew the woman Ted would marry would be or would;ve just been a college student, combined with the fact that it would make sense that ted would meet her at barney;s wedding, and that it would really make them uncle barney and aunt robin to ted;s kids (maybe it;s me, but i think it;s creepy to call your parent;s friends aunt and uncle whoever if they;re not a biological or by marriage aunt and uncle whoever).
that brings us to this episode where ted is dating a hipster twenty year old much to barney;'s excitement, until ted shows him her picture and he realizes ted slept with his half sister. This was cute to watch because it means that Barney has gotten to the point of closeness with his father;s family that he knows and somewhat cares for his half sister (and hopefully is done competing with his thirteen year old half brother) but it has been made clear that carly is not The Mother.
putting that possibility to bed makes it seem all the more likely this would be the show's last year, but now it would appear that is not the case. the only thing i could think of for the nineth season would be to explain why this story/girl was so important to tell the whole thing.
the robin plot was also another end tied up because robin for years has coasted along being the hot girl who guys buy drinks for and gets very upset when it is implied there is a girl more attractive than her in the bar, and now she;ll always have someone to buy her drinks (cue the awww)
on another note, they need to find something for marshall and lily to do, they need to be fun again. they could leave marvin on a bus or something (calm down, obviously they;d get him back, i;m just thinking outside the box!)