Ideally there's little difference, like Google Reader. There's a web interface and a mobile app that syncs with it. (Do people really use a desktop client? If so, why? Seems like a relic of another age, like desktop email clients.)

I want to choose which mobile app to use, I don't want to be tied down. Reeder, the RSS client I use, supports several Read Later services, several blogging platforms, tons of social networks, bookmarking sites, and Evernote. That's why it's so invaluable to me, and there is no other RSS client that's nearly as versatile. That's why I just want a new backend to replace GR, and since Reeder already supports Fever on iPhone, that'll probably be it for me.

Also, I still use a desktop mail client (OS X Mail), because it integrates well with my OS and it's scriptable. I like having local copies of my mail and attachments, and it's automatically backed up. The mail is also stored on IMAP servers so I can access it on other devices. I have over 100K emails, going back to 1994. There's no way that I'm going to rely solely on one web based service like GMail for that.

I've been a Google Reader user since 2006 and have rarely seen the website. I used NetNewsWire for years, then Reeder. For me, web apps are good as sych engines between native clients, and emergency back-up ways to access data from other machines.

Sure, we're getting off topic, but how is a desktop email client a relic of another age? Especially since the first decent webmail application with "modern" post-1998 features such as a decent split view is less than a year old (outlook.com)?