I disagree it is 'pretty peculiar', I think it is 'pretty obvious' why Adobe has done this. After years of growth and dividends and success, they have gone through a decade of sideways motions where they are resorting various and sundry cost cutting moves to keep their stock afloat. They have 'good enough' disease.

That is the disease where computers and their products which run on those computers have become 'good enough' and their customer base isn't rolling over every 12months to pony up an upgrade fee. One of the interesting ways to see this effect is to look for sales of technical books about older versions of a particular software. When they are still selling well it is because those folks are using the 'old' version rather than upgrade.

Given the pricing model Adobe doesn't have a good way to capture that market. They have aggressively been trying to shut down re-sale of older versions on Ebay and elsewhere but the courts have handed them a couple of set backs too because their licenses do actually allow it.

So they have a product, Flash, which they have already said is 'dead' [2] in that its future is maintenance only, and so they perhaps figure, what the heck, lets get some money out of it before it goes.

[1] http://www.google.com/finance?chdnp=1&chdd=1&chds=1&...

[2] http://money.cnn.com/2011/11/10/technology/adobe_flash/index...