Great ideas, some concerns though...

[JJonte]

It’s really ironic that Google just announced this, I’ve recently
spent a lot of time thinking about this exact problem. I think it’s a
great idea, but I have a few concerns regarding the technologies used
and terminology.

1) Don’t call it a manifest - http://code.google.com/chrome/apps/docs/developers_guide.html#manifest.
It’s not a manifest, manifests indicate what something *contains*
(i.e. shipping manifest), not what it *is* - http://www.google.com/search?q=define:manifest.
This may seem inconsequential but in the context of HTML5/AppCache,
which *already has* a concept of a manifest
http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#manifests
(and it’s actually a manifest in the definition sense). Repurposing
this term to fit these installable applications, especially when these
installable applications are going to most likely have an AppCache
manifest, is just going to introduce confusion. What should it be
called? I don’t know, I need to think about it more. Any ideas?

2) Don’t use JSON for the manifest. By using JSON additional
parameters cannot be introduced without worrying about naming
collisions. I know there’s a lot of consternation surrounding XML
right now, particularly the amount of complexity it (supposedly)
adds. Dave Winer has a really great post on this -
http://www.scripting.com/stories/2010/05/19/theHavocTheXmlPuristsWroug.html
, just posted today actually, about how to just of think of XML as
elements, attributes and *namespaces*. Namespaces are critical for
the manifest; they allow new elements to be introduced without
worrying about naming collisions. So new elements can be created by
the end developer and more structured data can be added to the
manifest - things like target screen resolutions, PICS ratings,
required browser capabilities, description, categorization.

3) I see "magic words" sprinkled through out the spec (i.e.
"web_content", "name", "icons", "permissions", "24"). This is
directly related to #2, but use fully qualified names (http://
chromium.org/installableapps/#name, http://chromium.org/installableapps/#permissions)
as opposed to these short, generic, and magic character sequences.

Don't take my criticism as a knock. Again, I love the idea. I think
it's great this is being championed by Google. I would recommend
spending some time reconciling the AppCache manifest and the
Installable App manifest, from a few different perspectives: syntax
and semantics, purpose, and extensibility. I'm sure there's a better
way to do this - I just don't know what it is yet. If I have any new
ideas, I'll post them!

-josh jonte