It looks like we have done a circle. I mean to say, earlier people worked from home like farmers, weavers, goldsmiths etc. Later on, industralization and mass production created jobs outside homes. However, now with population explosion and decreasing land space, people are back to working at homes. Now, internet explosion has hastened the "work-at-homes" jobs.
There are a number of ways to
earn money online, like freelancing,
earning money through blogs,
linking, and many more options.