Registered, but Can't Post?

[Ludens]

I'm just curious as to how many posts it takes to be upgraded to above a junior member. I've seen many many users post like 10 messages and be promoted, and I've also seen others at 75 posts and still considered junior members.

What is the system that determines when it occurs for each individual member of the community?

Promotion is not based on postcount, but on participation. All that is required for promotion to full member is a bit of patience, and that you post regularly in a friendly and helpfull manner. You can find more information in the Guild FAQ. We don't promote members just because the post a lot in a short time, and downright spamming will at best delay promotion.