Pretty much everything new I'll work on will be responsive, and using the "mobile first" theory for designs. A lot of people read their mail on their phones and tablets, so I started sending responsive newsletter mailings this year and noticed an uptick in opens, click-thrus, and signups. Eventually I'll go back and retrofit existing sites to be responsive too. So any tool that a sponsor offers that isn't responsive will wind up being replaced with something that is.
I haven't looked into it, but I think there's probably a nice business niche for converting people's existing sites to fully-responsive versions.
</new-fangled hoopla talk>
Good to see you around again UW.