Your best passive income? (2014)

anyone?

It will sound banal, but Bitcoins I bought year-and-something ago.

Not much has changed since the last thread. Improvely (https://www.improvely.com) is still in the 5-digit monthly RR range and growing, and I do no outbound marketing other than some PPC ads that don't need much active management. Everything that can be automated has been automated (onboarding, lifecycle mails, dunning mails for billing issues, etc), leaving me free to spend all my time on support and improving the product.

Two things that fit the "passive" mentality that have been picking up steam recently:

1) I offer an affiliate program with a revenue share commission (upfront bonus plus 10% of the referred customer's payments for a year). A couple of my best customers have become my best affiliates, recommending the product on industry blogs they write for regularly. It doesn't get better than having excited customers marketing your product for you. In the early days the affiliate program wasn't doing much at all, now it's a meaningful contributor to subscriber growth.

2) I've been running Improvely long enough now (just over a year) that some of the clients are growing their businesses significantly. I've got quite a few marketing agencies on board, and they're picking up new clients and adding them to their accounts. As their business grows, and their usage grows, they upgrade to plans with higher usage limits. Same customer base, higher revenue per customer. In the beginning, a new customer was worth $30ish per month. Today that's over $70/m per customer on average.

No! Thats the funny part.. I am putting only IAds..