A bit of a ramble.

I think online is easeir in terms of casual fun, meaning finding someone in a chatroom to call "Master" for the evening.

But in terms of serious D/s relationships, I've yet to see anyone, anywhere provide any real backup to the "online is easier" claim, beyond stating it as if it's supposed to be some kind of fact. Very few offer much to back it up with. A lot of the "online is easier" thing seems to come from a group that refers to the "chat with someone for an evening" thing which I don't really consider a real D/s relationship to begin with (though I suppose that's a whole different debate). Which I suppose is at least half relevant to the wannabe/fringe group discussion in itself. People (generally) are very willing to label chatroom Doms as wannabees, but with subs there seems to be a lot more shades of gray permitted. I find it... interesting.

In terms of online being easier vs. reality for a serious, full time relationship, I guess that depends very much on what you're doing with it. If your D/s relationship is heavily based on tasking in various ways and reporting to your Master as one example (as opposed to, say, people really into bondage or masochism as examples), the activities you might be undertaking with your partner may not even change much based on the setting.

For me when it comes to moving online to real life, regardless of whether you're talking lifestyle or vanilla, I think it's probably wise to have an agreement about their being a "buffer period" of sorts on first meeting. No matter how crazy in love/lust(/whatever else) you might feel with someone online I think it's probably wise to meet in more of a friends capacity at first. If you then find that yes, the chemistry is definitely still there, then get back into the really fun stuff again. I think a lot of the "online is easier" thing when it comes to the serious relationshps probably comes from people trying to make the transition too fast, when maybe both parties could benefit from that "buffer period".

So to sum that up I don't really see "online is easier" as a D/s issue as much as a relationship issue that spans any style of relationship and how one makes that transition from the net to the home.