For me at start it was more out of necessity, to find a viable
alternative to earn some extra income, due to some difficulties
to develop further my other career.
Now, after almost three years, is the main income source. But it hasn't eaten away the passion to do it for fun. On the contrary.
The financial security permits to have time to develop personal
works and more complex projects (not necessarily for stock).
In five years from now I'd like to have built an established 'brand' in microstock, as stated in the excellent Ellen Boughn's blog.
Parallel to that would like to have established a name also in more 'creative' photography, for which I'm building a portfolio right now.
What is your experience, your motivation and your final aim?