Unless it changed recently, Marco Arment, the creator of Instapaper, is an advisor to Arc90, the company behind Readability (http://www.marco.org/2011/02/01/readabilitys-new-service)

Marco is not currently listed in the advisor team at the bottom of their about page (https://www.readability.com/about). Would seem like a conflict at this point and makes sense for them to move in separate directions.

Doesn't seem incredibly surprising; Marco isn't really innovating effectively, and it's time to see the space build via competition.

I beg to differ. Instapaper 3.0 was an amazing step forward for the software.

Personally, I have found that Instapaper 4.0 (I assume this is what you meant when you referred to 3.0) has regressed. Archiving read stories, for example, used to be one click - now it's 2 or 3.

Automatic/background downloading fails sometimes, often I see articles unavailable (I don't often remember to check before I leave wifi/signal, so it's a pain to find this out when I expect it to work behind the scenes).

Marco's concept of darknet social networking/sharing is great in theory, if he were working for MS Research or something, but in reality, it's confusing and challenging: I want to share stuff with my wife and find it incredibly hard to know if it got there without having to bug her to find out. So we resort to emailing it back and forth - which completely breaks the model.

There's no semantic layering on top, exporting to the kindle is tricky (it wont, for example, guess that i've read an article exported to the kindle, and remove it from my list..)

I can't have it archive and send stuff to pinboard easily -- and if i want to do anything with the API, i better be prepared to pay a weird licensing fee.

As much as I want to support Marco, and I really do, he makes it really hard for me to be enthusiastic about what he ships, and I feel that his support sucks.

I'd bet 100$ he's reading this thread, but he won't engage - and that's really striking. I often wonder how things look from his ivory tower.

I'll second that. Instapaper 3.0 is incredible.

I use Readability and Instapaper for different things. With Readability, I use the Chrome extension to make articles readable in the same way Safari does on the fly.

With Instapaper, I save articles and read them later on my iPhone, and I get a collection of articles that I've saved sent automatically to my Kindle every Friday. Saturday mornings with my Kindle, saved articles through Instapaper and French Press coffee? Life is good.

Is Instapaper the only one with the read later offline feature? (versus Safari Reader and Readability)

In what way? I ask bc I agree with parent (and disagree with you), as far as the iPhone version of Instapaper is concerned.

Kind of surprising to me since the arc90 team worked with Marco for the original platform effort.

... and a response to Apple's move into this space

Marco doesn't seem to think Apple's service will challenge his business model for Instapaper much. Do you think Readability feels differently?