The last big thing was Skype which was a nice jump forward for those of us who were techno savvy and liked the idea of very high quality call audio and zero cost.
An unfortunately side effect of "big things" is that they ultimately segregate the efficiency of a single point of contact, and single point of contact information.
Back in the day when I was a kid there was a family phone and a family phone book next to it for contacts. If you wanted to know the phone number of someone you knew, it was probably in there, and if you were the sort that liked that kind of thing then Speed Dial could make life easier.
Go forward 10 years and it became two phones (land line and mobile phone) and two phone books for your contacts if you were the type to watch your pennies and try not to spend too much on your mobile bill.
Go forward 5 years and it became three phones with Skype, land line and mobile phone and potentially three phone books for your contacts, or messing around with your mobile phone to get the number for someone.
With the possible addition of web page based telephony to this for discount priced calls to mobiles in other countries etc. we're potentially looking at four phone books to maintain or the continuation of mobile phome messing.
Which ultimately leads to a point where the mobile phone is such an easy way of making calls without messing around, will lazy people look anywhere else when the efficiency of the single point of contact and single point of contact information exists there? and will the juggling of phones remain the past time of the techno savvy miser?