Building up passive income online is like rolling a snowball down a hill.
Of course it gets bigger and bigger as you go along and that is the whole point. You have to put in a lot of work and effort in order to produce this growth but the income is still largely passive because once you achieve a level of income that you desire then you can cut way back on your efforts and still maintain a healthy income.
For example, I can spend about 30 minutes per day on my websites while I work at home and my income will flatten out or even rise slightly month after month. I have done this in the past and witnessed this slow growth first hand but normally I am putting in extra work above and beyond 30 minutes per day on my websites because I want to see the income grow.
The point here though is that you do not have to continuously work like a dog just to maintain your income level….you only have to work like a dog to significantly grow your income level. Right now I am making about 300 per month in passive income from my websites but I am forecasting this to be around 500 within a few months here and possibly up to $1,000 per month within a year or two from now. These are not unrealistic expectations because only a few months ago I was only making about 100 per month in income, not I am at 3 times that level.
Now my question is going to come up at some point when I am exceeding my day job income with my online earnings and at that point I am going to have to think long and hard about quitting my day job and moving to exclusively earning money online. To continue working a day job is to throw money away because obviously I could grow my online income even faster if I were to dedicate 40 hours per week to it.
The other nice thing about making money online is that if you do it by targeting keyword traffic through search engines (and then monetize that traffic, such as with Google Adsense) then you will find that it does not get any harder to keep the snowball growing in size. In fact it gets easier because you are building up link authority and more resources for networking through additional websites. Also there is no problem with scale as you have no customers or inventory to deal with. You can just keep growing and the only thing that will go up is your income and possibly the number of comments left on your blogs.
In other words there is plenty of room to scale an income like this without having it increase the level of work needed to maintain it. That is what makes it passive; that your income will grow but the headaches will not grow along with it.