Small stakes, but completely passive. About ~$500/mo from Adsense on what are essentially niche long-tail SEO targeted yellow-page-like regional sites for very specific verticals. Not a lot of money, but I haven't touched them since 2007 (when they were averaging closer to $800/mo). Initial investment was mostly time doing research, implementing, and SEO stuff. Also experimenting: abandoning failed sites or improving ones with potential. Now the successful ones are completely passive sources of income and the only expenses are hosting and domain renewal.
Right now I'm working on a more substantial side-project that will provide an actual service that hopefully people will actually want to use and subscribe to for their businesses. It will require more maintenance and time and monetary investment, but in the long run should be much more satisfying and potentially bring in more income.
Right now I'm working on a more substantial side-project that will provide an actual service that hopefully people will actually want to use and subscribe to for their businesses. It will require more maintenance and time and monetary investment, but in the long run should be much more satisfying and potentially bring in more income.