That's all my paraphrasing of Dropbox' announcement. Dropbox has tried as hard as they could to be nice about it. It would be interesting to know the proportion of PPC Mac users who are and aren't paying for the service. Somebody who wanted to develop a replacement service might be able to make hundreds of dollars doing so, and I suspect Dropbox just saw that it wasn't worth the effort.
If you want my version: Stop using a ten-year-old computer that hasn't gotten security patches for seven years as your main computer. Stop using it as your second computer. Take it off the Internet altogether.
To be honest, given the number of people using PPC Macs as their main computers who are so mistrustful of the cloud, I was surprised to see the particular backlash that I did, over on macrumors.
Not to be that guy who does the "Why are you even using a Mac?" thing, but, well. Since that's my schtick, here it goes.
If you don't trust Apple, and you aren't willing to run modern hardware, why would you use a Mac? It's one thing to have such a machine as a hobby computer (heck, I want to pick up a late G4 or a G5 of some kind as a local-only 10.5 box to run some apps I still have from that time period) but I'd say that it's pretty unreasonable to try to use such a machine as your only or main computer. The myth from the late '80s and '90s that Macs had a lower and TCO and a longer lifespan has been proven incorrect over and over again, and it's well known that Apple will happily increase the system requirements for the OS and prevent the use of dozens of models at the drop of a hat.