What happens if websites change their terms?

Technology Review has a story about Kodak's online photo service, Kodak Gallery. Apparently they used to provide free storage of photos but this recently changed. Someone who had photos stored on their service got an email from them saying that Kodak will delete her picture albums unless she spends at least $4.99 by May 16 and every year thereafter on prints and other products. That's the new rule for people whose photos take up less than 2 gigabytes of space on Kodak's servers -- enough for around 2,000 1-megabyte photos. And customers who signed up under the old rules won't be given a pass. Kodak's decision to change its policies illustrates the risks people face as they increasingly rely on privately run services to handle their digital memories and communications. These services often state in the fine print that they can change the rules at any time, and users have little recourse when they do.