Chopping up rarely works. Perhaps in a conversation where the first 30 minutes are conversation, and the second 30 minutes are an on-screen demo. That would work, because perhaps I'm only interested in seeing the technology demoed. I'd prefer it if both clips were posted simultaneously though. Perhaps even in a single post, and with a metafile so that both play consecutively if you want, like blowdart suggested.

Otherwise, chopping is a bad idea. If the conversation is 40 minutes, chopping it up into 4 10 minute videos is just going to be annoying. The call for shorter videos was for actual shorter conversations, not shorter clips.

Basically, what I'd find ideal would be a couple of short, 15 minute conversations/demos every week, and maybe a 40-60 minute video once or twice a week, so that you can get a quick update regularly and get into the deep stuff when you have the time.

If a video is very long, and it is clearly dividable into two or three clips, that would be okay. I imagine this, as described above, as for instance a 30 minute talk on technology and then a 20 minute demo of said technology. Or perhaps a 20 minute overview of a certain technology, and then a 20 minute in-depth look at a certain aspect of that technology.
Cutting that in two would be okay, if both clips are posted simultaneously and an easy way to play both one after the other is provided, so that I have the choice to only watch the tech demo, or perhaps watch the whole thing all at once.