Hmm, I'd disagree. One can "invest" in future consumption. In the income function Income=Consumption+Investment, consumption is present consumption (ideally). If you buy a house to live in, that's an investment. Even if you're not working, just collecting social security and drawing down savings, you're investing in your future living standards. Even running a server farm is in the end just postponed consumption (whether consumption in goods/services or consumption of the comfort of having savings rather than living on the edge).
+1 and :thumbsup: to that.
There is an economist currently at the "New School" formerly of U of Mass/Amherst(?) named Richard Wolfe, recently interviewed about 10 times by Bill Moyers on PBS. One of his assertions: universities really have "two economics departments" -- Economics, and Business Administration. The latter multi-discipline track tends to use the word more restrictively.
Suppose there is a commodity -- a durable good -- which you "need" more than want. It has a time-stream of benefits (returns -- not exclusively in dollars) over its lifespan. Your "investment" assures that your needs will be met at a certain reliable level -- perhaps long after the item has finished a straight-line depreciation schedule.
You can earn money with your computer -- I did with my various PCs over 20-some-years. You also save time, which can be translated into money, even if it is "leisure time." Then, there might be the improvements you make in managing your money, filing your tax-returns, or generally living with a modicum of discipline. I can think of myriad ways your life is improved, labor time decreased or various other facets which don't directly provide an "income stream" deposited in your bank account.