I think he's referring to the browser closing in the background as memory is used by other apps... But that happens in all versions of Android to one degree or another depending on how much memory you have, stuff running in the background, etc.
You'll have to forgive me as I've yet to handle ICS first hand (no VZW in Puerto Rico), but here's what I've observed thru Froyo, GB, and HC...
On Froyo and/or the original EVO my browser closed itself in the background all the freaking time, I couldn't switch thru more than one or two apps without the browser getting paged out of memory... And when I'd come back to it the thing would only reload one tab/window (if that), the rest were ignored.
On my EVO 3D and GB the basic behavior is the same but I can cycle thru half a dozen apps and even a game and the browser will probably still survive and not get booted out of memory. Obviously this is because the phone has twice the amount of memory as the previous one. Certain apps are more memory hungry than others and still force page the browser out of memory tho, Gmail seems very prone to do it... And when it gets kicked it only reloads one tab/window at best. I also had to hack the browser to get more tabs out of it because HTC keeps locking it at 4 for some weird reason.
On my Honeycomb tablet the browser always reloads every last tab I left open whenever it gets paged out of memory while multi-tasking, which is awesome imo and I'm guessing that's how it works in ICS too... However, I've noticed it does get paged out much more often than my phone's browser, which leads to the frequent refreshes the poster above alludes to.
Whether that's because I usually have more tabs open on the tablet or because it takes more resources to render stuff on a larger/higher res screen I cannot say, probably a combination of both. I always figured HC wasn't very well optimized anyway since the browser crashes more than on GB, dunno if it's any more stable on ICS.
Unfortunately if you often find your browser reloading when you switch back to it I don't think there's much you can do beyond rooting and trying out ROMs with tweaked memory handling, etc. I do think things like the browser and launcher should have higher priority when memory's being handled but I guess that's not always the case. You could try some other browsers too... It's quite possible leaving a video paused within the browser raises it's memory consumption significantly too, thus making it more likely to get kicked out. Flash isn't exactly a model of efficiency...
Hell it wasn't until a month or two ago that they finally got playback controls on Flash video polished enough to the point where they're finally semi-usable on phones... All that after having already given up on Flash, Adobe really was it's own worst enemy.