There's an excellent interview on Exponential Audio with Erik Zobler, his credits include Michael Jackson, Miles Davis, George Duke, Donna Summer and The Brecker Brothers, to name just a few. 

In the article when asked about online collaboration he says this:

So you don’t think that online collaboration can do it?

“I was going to say that. You were talking about this whole thing of sending files to everybody and getting them back. Don’t get me wrong, it is a great way to get work done, but the really great thing about having a band and tracking a band together is that the bass player and the drummer will just look at one another and drop at the same time. And the pocket... There’s a feel thing that happens when all the musicians are playing together.  You just can't do that with online collaboration, can you? At least not until we change the laws of physics! You're just not there to be able to have instantaneous interaction. I think the problem with some modern recordings is that people are starting all the bits of patchwork and working somewhat in a vacuum.  Do you know what I mean?  Rather than trying to weave a beautiful piece of fabric together, they're trying to just stick externally fabricated bits together.  It’s not necessarily bad – hey I do it all the time – but it is not my preferred way to make music.”

He's right, there is nothing like sitting in a room with other musicians and seeing their eyes, a nod from a drummer to a bass player, a smile from a producer as the guitar player cuts a great lick. It's just as necessary when working with classical musicians who are responding to one another as well as the conductor.

I've spent some of this week with producer Paul Drew and one of my writing partners Jess Hammond. There was a specific moment during a lyric write when Paul said he wasn't sure about a certain word, I then said argue the case with me then. We spent a few minutes talking back and forth until we had settled the matter. There were numerous times like this during the sessions. We all know how easy it is to misunderstand the written word in emails or texts and with something as important and dare I say it emotionally charged, I don't think I would trust myself to that medium. We would also have moments during the tracking of the idea when we would smile at one an other with an unspoken 'here's a great moment.'

Of course as Erik says we all use modern technology, but it is not his preferred method way to make music.

I send files back and forth to musicians and other collaborators as part of my process, it's a great option to have, but there is an essential part of music collaboration that technology can't replicate.

There'a story I love of a Father woken one night in the middle of thunderstorm, he runs to the room of his young daughter to check she is OK. When he walks in she is standing looking out of the window at the storm. He tells her not to worry because God is keeping her safe, to which she replied 'but Daddy I want someone with skin on.'

I think that's where I stand on this, when it comes to making music I prefer making it with people who have skin on.