The short answer is: I don't know. Or rather, it is not easy to draw a clear distinction and say, this is, and this is not, a part of it. Some purists seem to think that if it's not free, it's not sharing. That means that some of the companies most often mentioned as examples of the sharing economy, such as Airbnb or Uber, would not be part of it.
Yesterday I was talking to a friend who claimed that companies such as Taskrabbit (or Swedish Taskrunner), should not be counted in, since they're not about sharing any physical assets but rather people's time. It's just like being any kind of consultant or freelancer.
And to make it even more complex there are many other phrases used for basically the same concept, such as collaborative economy, or trust economy, or peer-to-peer economy.
I think I will have many reasons to discuss this topic further during the year. But regarding my project I have decided not to rule out anything from the start. I will use Airbnb, Uber and Taskrunner, as well as free sharing services, such as Hoffice (where people create free work spaces in their home). And some old school sharing too. Like helping friends, borrowing things from people I know or hitch-hiking. Which also raises an interesting question: Is the sharing economy the same old sharing (or the same old economy)? Or is it a new thing that is changing everything?