Google Cloud Platform has launched Google Cloud Storage Nearline, a service which allows you to back up infrequently-used but potentially handy data into Google's Cloud and then retrieve it later. The storage costs are very low -- 1 US cent per GB per month while the data is at rest.
Superficially, that sounds similar to Amazon's existing Glacier archiving service. The key difference is the recovery times: Google claims that even at-rest data can be recovered within approximately three seconds. Glacier specifies data retrieval times of several hours.
That alone won't make everyone switch; for existing AWS developers, Glacier integration will be much easier than trying to work with a separate platform. The fact that Google is charging essentially the same rate (1 US cent per gigabyte is also what Glacier charges in US data centres) for a much faster retrieval time is unlikely to be ignored by Amazon for long, though.
As with any cloud storage package, it pays to check the details. While the service is in beta, no service-level agreements (SLAs) apply -- so if you don't get those claimed sub-3 second retrieval times, you won't have any formal grounds for complaint.
You also have to consider overall costs. Any data deleted within 30 days will still be charged for that full period, and you'll also pay retrieval (egress) fees when you access the data. In Australia, those rates are set at $0.19 per GB for the first terabyte, $0.18 per GB for 1-10TB, or $0.15 per GB for volumes above 10TB.
Introducing Google Cloud Storage Nearline: (near)online data at an offline price [Google Cloud Platform Blog]