I vote for keeping DAC and for Cooperative to replace the C in DAC. I think there is also merit to being able to be flexible with the C (Company, Community, Cooperative, Cabal), but being flexible with the C makes marketing more difficult and might actually confuse newcomers.
Decentralized application just makes me think of some new take on peer to peer tech, which to some extent is the truth. It just doesn't sound as compelling. If I didn't know better and I was new to BitShares, or even Blockchain technology, it might make me just think 'Meh. That doesn't sound interesting or revolutionary.' Digital Autonomous Corporation does sound interesting and revolutionary, perhaps even more so than Cooperative. But I understand the need to perhaps move away from the Corporation metaphor and it could be argued that Cooperative is more accurate any way.
On the subject of Autonomous, well I think Autonomous is exactly what BitShares is and is striving to be. Being autonomous is not the same thing as being unmanned:
http://dictionary.reference.com/browse/autonomyI've said it in previous posts, if we have to move away from the Company metaphor, and there are some benefits to doing so, then
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Cooperative would be top of my list.
http://dictionary.reference.com/browse/cooperativeCooperative speaks to me of both people and economic activity and cooperation. It makes me think of an entity that does something useful and is actually productive too. A single cooperative often produces more than one product - traditionally it might have been wine, olives, cheese and/or wheat, in more recent times a cooperative may look like any other more centrally orchestrated big brand producing more than one good or service too (e.g. the John Lewis Partnership or The Cooperative here in the UK). The idea that people who join a Cooperative can just branch out and start cooperating to sell strawberries alongside their olives, wine and wheat is appealing and fits with how I at least see the SuperDAC evolving over time. Swap out these crops for X, DNS, VOTE, etc and you can see where I'm going with this metaphor. If there's enough interest in 'growing' a new product then members of the cooperative will organise together an make it happen.
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Cooperative is still intriguing enough and accessible enough for the average non-geek to want to go and find out more. Also most people understand what a cooperative is and that it has some economic component that aims to distribute wealth in an fairer more even handed way. This is why I much prefer it to Community which I see as a more nebulous and less accurate description.
I agree with some of the other commenters that DAC has started to enter the lexicon and as such I think it would be a real shame to kill the term from a marketing point of view. The marketing capital that has undoubtedly built up surrounding the term, or at least the acronym, is important and hard won. I'm in favor of trying to keep the term DAC in some form if we can.
Blockchain and decentralized application - these are not terms that are going to resonate with your Average Joe IMHO. With my geek hat on I can see why they might appeal though.