Ask HN: Examples of sites with 'customer class' freemium?

http://amcharts.com/ is one example I can think of. You can use it for free if you don't mind "charts by amcharts" in the corner. This makes it possible for free personal use, as well as the ability to try it for free, but if you want to use it on your business site or software, most would surely pay the fee.

At http://xp-dev.com there's no SSL on the free accounts - those users who want tougher security of their code transmitting over the wire do have to upgrade. (disclaimer: I own and run xp-dev.com)

I've seen several. Search for "Personal Use only" maybe? Those are generally the terms I see when I see the licensing model on a shopping cart. I don't know of any offhand but that's probably where I would start.

Most of the "backup services" (jungledisk, mozy, etc.) do either free or really cheap "personal" backup, but have expensive "business" plans.

RubyMine is free for "Open Source".