I suspect one of the first criticisms that Liberty.me will face is that it’s creating an ideological echo chamber for libertarians. The thought is that this will make participants more ideological, separated from reality and hostile to their ideological competitors. I don’t think this will happen, as Liberty.me isn’t focused on reinforcing ideology, but I suspect someone will claim as much.
Here’s a potentially neat way to pre-empt the problem: a “Challenges” category of topic, news, etc. I’m not sure where to put it, but it could link to articles and ideas and books critical of liberty. That way, people could choose to confront themselves with challenges to liberty in a direct way.