Readability is not like the Betamax (as Mike D posits) for one simple reason: Readability went from being a content time-shifter (legitimate, see Instapaper, see Betamax) to becoming de facto paid content brokers (illegitimate, presumptuous, and yes, scummy), time-shifting and taking money on behalf of content creators they have no relationship with or permission from. It’s the latter part that turns the ethical into questionable.
If Sony had tried to monetize not only the hardware of the Betamax, but was collecting money for shows that consumers time-shifted, then they are agents of a financial transaction that would have obliterated the fair-use arguments that they won their case on. That the payment is voluntary does not change this, just makes the water muddier.
Readability failed when they brought the concept of commerce for content into play.
Maybe a better analogy would be this: I’ve just designed an awesome service. It takes other people’s apps and puts them all in one easy-to-use and beautiful place. I add better design as a service. And if you give me some money, I’ll see that I spread it out among the app developers who register with me or bother to reply to my email. It’s only the fact that it’s currently impossible to do this makes it ridiculous, right?