[kevin_thibedeau]

The thresholds for unlocking privileges are there to filter out offensive trolls and other drains on the community. This can be a bit annoying since it applies separately to every subdomain and I can't be bothered to build up rep in every place that I might want to make an occasional comment.

[shagie]

Once you have sufficient rep on one site, you get 100 rep on all sites which is enough to comment everywhere.

[mark-r]

The +100 that you get for signing up on a new subdomain is supposed to get you over that hump. But I don't remember how much rep you need to get the signup bonus.