Obsolescence comes in many forms, one being the natural kind, the other planned. Then there's the suddenly, unexpectedly enforced kind, which is rarer but which reared its ugly head today with one of Google's more innovative, but old, ideas.

Of the dozens of Google experiments over the years, some in "beta" and some in "release" form, not all survive to adolescence. One that is due to expire next week is Hello, an interesting take on person-to-person photo sharing that, on its face, sounded like a good idea.

"We originally embarked on a mission to make photo sharing easier and more fun with Hello," reads the service's main Web page now, which notes the service's expiration date as next Thursday, May 15. "We plan to keep carrying that torch in new projects to come."

Hello was essentially an instant messaging conduit for photographs as opposed to text, with some post-processing capability built-in. Each member of the service had both Picasa and the Hello client installed on his system; Picasa, you'll recall, organizes and presents photos that a user has stored locally, not in "the cloud." When both members had Picasa open, one could effectively send a photo from his personal Picasa space to that of the other Hello member with a simple button click. Hello also had its own IM chat program for those whose sessions mainly centered around photo sharing.

Alternately -- and this was a fairly interesting concept -- the member could instantly post any number of photos to his personal space on Google's Blogger service, by directing them to the IM buddy name BloggerBot. That bot would receive the photos, size them to fit the blog automatically, and place them in the blog's album without human intervention.

It all sounds like such a nice idea, really; but perhaps one way you get customers to use sharing services that involve "the cloud" -- Internet-based servers rather than their own local hard drives -- is by removing access to the alternative. As a check of Google's latest promotional material for Picasa shows, new Picasa users are entitled to 1 GB of online storage for use as an online "Web album," with more storage available.