Trend Watching's definition of a minipreneur is as follows:
We have dubbed this trend 'MINIPRENEURS': a vast army of consumers turning entrepreneurs; including small and micro businesses, freelancers, side-businesses, weekend entrepreneurs, web-driven entrepreneurs, part-timers, free agents, cottage businesses, seniorpreneurs, co-creators, mompreneurs, pro-ams, solopreneurs, eBay traders, advertising-sponsored bloggers and so on.
With all of the amazing available resources these days, it seems like this trend is only going to continue to grow and grow. And to that I say "Holla!"
For further reading on minipreneurs, here's a load more info.