I remember sitting on the carpet at CSCW 2014 talking to Gabriel Mugar about boundaries and how people becoming aware of them. I've been working on some thoughts re. "barriers" being the wrong word because one imagines a passive wall of some height/permeability that can be removed or opened -- hence "lowered".
In the case of active socialization as some newcomer is welcomed to some established community, the "wall" is more than "lowered"; an active aid of conveyance across some threshold is provided. Here, Latour's door opener doesn't just make it easy to enter a building but also communicates that you are welcome. If we were to apply the barrier metaphor of a "wall" that might be lowered, we might imagine a simple hole in the wall being the lowest barrier. But when thinking about active socialization, a hole in the wall with a "welcomer" is more open. Does the "welcomer" lower the "wall" further? No. Suddenly the idea of "lowering as barrier" gets in the way of thinking clearly about the difficulty people experience when transitioning from "outside" to "inside" of a community.