I was disappointed in the WIlliam Bell plot thread! After all that build up about WIlliam Bell it just seemed anit-climatic! He had no ultimate knowledge to impart, he wasn't the evil mastermind of the show, he wasn't it's chosen one/hero either! He pretty much just showed up said "Hello I'm WIlliam Bell here's how you get home" and then disintergrated! He wasn't important to the overall plot at all! They had been hinting since the start of the show that he was somehow the key the whole thing! It was a total let down! But other than that I enjoyed the episode!

I was pretty impressed with the episode.  More so than any other past episode in the series, it made me want to watch the next episode right away.  Unfortunately we'll have to wait till the Fall.   I was kind of hoping for a Walter/Walternate meeting, but I guess that's going to be a gem they'll save for later.

I have to say, in the days of good shows getting cancelled too soon, I am starting to relax on the not super blatent product placement.    Shows like Fringe are expensive to produce and of course those costs factor in to the shows being renewed.  You can tell Microsoft is starting to invest in a lot of these shows as you'll see on Fringe and Smallville that they tend to have blantent Windows wallpapers or prominent Windows logos on laptops.  None of these bother me too much, because they are subtle enough.  Now if they get to the point where characters arbitrarily state things like, "this blankety blank sure is awesome where can I get one....", that would be another thing.

I didn't mind that Bell's character was toned down.  In fact I was surprised to see him last week.  I thought I had read a few months ago that Leanard Nemoy was retiring from acting.  Guess he held off to at least do these parts, or maybe these were already filmed.

Once we saw Olivia change hair color, I knew what what was gonna happen.  I also realized that when they showed the tatoo Oliviate had it was for a reason.  Now, I wonder how long Oliviate will be able to keep the facade of bing our Olivia.  Who will realize it first?

Now, with Peter and the doomsday machine: I think he's the perfect candidate becase he's technically from 2 worlds now.  He was born in the alternate universe but he spent considerable amount of time in ours, so his molecular makeup must be composed of both now, making him quite the oddity.

Going to have to be clever writing to keep Alt-Olivia undercover. I saw it coming but wondered how in the hell that would be a good plan? Seems like she'll be burned the moment she talks to Peter. He IS incredibly observant after all

Great episode. What I liked most about the Oliviate (good one Funkatron) crossing over was they almost made it obvious. Like they knew we wouldn't be that stupid to not figure it out, so they just kind of went along and assumed we knew what happened. Kudos to the writers for that. I also thought Charlieate would figure out it was our Olivia since he had worked with her for so long. Figured she'd do or say something not like Oliviate.

I was also glad that with a quick few words, we find out what the definitive difference is between Walternate and our Walter. The whole removing part of his brain thing was very effective as a plot device. 

They're gonna have to think of something really good to be able to get Olivia back to our universe. William made it sound like he was the only way they could conjure up enough juice to get the device to work. Now that we're presuming he's dead (alternately; retired), something else has to do it.

I can't wait for next season. I can't get enough of this series.

The cell they put Olvia in reminded me of that little burned corner at the school where Olivia was given Cortexiphan.... I wonder if this is how she is terrified into getting more in touch with her "powers' and will evetually use them to cross-back over.

 One thing about Oliviate crossing over.  Did she ever get the drugs that gave Olivia her abilities?  Otherwise, she should not have been able to open the portal.  It did seem like the plan to send her back was a last minute thing, what they discussed over the com links.  So it's not like they had time to does her.  And there is no indication that the alternate universe developed the same drugs anyway.

As for getting Olivia back.  It seemed from last seasons finale and the season opener that she can get herself back and forth on her own.  It was crossing over with other people that needed the big power boost. 

@thorin02: they talked about using Olivia to cross back over, but decided that her powers weren't strong enough, so they built that device! It was then Bell's atomic body charge that pushed them over to the other side! I'm not 100% sure but I don't think Olivia was required to do anything at all!

 But that would mean they effectively duplicated Walter's original device which is what caused all the problems in the first place.  And if that wasn't what they did, then why did they even need Olivia to get there to begin with.  Walter seemed pretty certain in the last episode that using his machine to get across would just make things worse.  And as the device was described it was a doorstop.  Something else opened the portal (presumably Olivia) and the device provided the necessary power to get everybody back.  

Did that change in the ten minutes between Bell describing the device and it actually being used?

@ NotAFan - I suspect that the writer's didn't have much of a choice.  Unless they signed him to a multi-season contract (which is never done for guest stars), they cannot force Nemoy to come back if he doesn't want to.  They may well have had grand, multi-season arcs planned for the character, only to find out that wouldn't happen because Nemoy was unwilling to do it.  Once he made the decision to retire, they probably had to scramble to come up with a way to write him out of the show.  And which would bother you more: the ending we got, or seeing Bell recast as another actor (who couldn't hope to mimic Nemoy's very distinctive personality).