[acanby]

I think this stems from the memory these people hold that the item (whatever it is, doughnut, site access etc) was once free. People will wonder "why did this change?". It could be many things, but people will most likely jump to the easiest conclusion, the seller is greedy.

Using the doughnuts analogy, I wonder how things would have worked out if they continued to give away the plain doughnuts for nothing, but added a new line of premium iced doughnuts which attracted a charge? Personally I wouldn't mind, and I think that a lot of people would be ok with this.

Stemming from this, you really need to have a good reason to charge people for something they were previously using for free.

Personally, I don't think you can start charging for something that was previously free (without significant value add). By all means offer a paid upgrade with particular value add, but never do the wrong thing by your (thus far) loyal users.