That's a good question.
I actually wouldn't expect anything besides that the contracts of the rates/services/plugins that were define at the signup aren't changed afterwards.
I want to have a 'workable' solution in the free segment. Gliffy for example reduces the amount of saveable diagrams to 5 and disables the sharing. But still I can paint all the diagrams I need. Now I am a paying customer
Nowadays I don't really use freemium besides tryouts for software. I even sponsor intellij/library plugin authors. So maybe I am not the best example for a 'free software user' anymore.