- Speed - Google Reader has a set of keyboard shortcuts that make scanning a large number of feeds quick. Really quick. While Netvibes also offers keyboard shortcuts, out of habit, I tend to use mouse-clicks to navigate between tabs and articles.
- Flexibility - You can read related blogs that are grouped together (e.g. Oracle, Wordpress), read an individual blog or quickly skim over a river of news.
- Sharing - Occasionally, I want to save an article for future reference or potentially sharing with others. These items might be interesting or useful snippets of information quickly noted in passing which I wouldn’t necessarily blog about. The most obvious place to mark these items is right here in the RSS reader as opposed to a static bookmark. The list should (obviously) be visible as an RSS feed. Google’s shared and starred items make this easy (single keystroke).
- Flexible interface - I really like the full screen mode and the options for ‘list view’ where articles are condensed apart from the current article and ‘expanded view’ (all articles are expanded).
- Statistics - I can’t decide whether the trends page about your personal reading habits may actually be useful or just a gimmick.
Here’s a Flickr set of annotated screenshots to illustrate the functionality in Google Reader and the flexibility of the interface. I think the recent addition of subscriber counts to Google Reader will show that Reader has a substantial and rapidly growing share of the RSS reader market. Stowe Boyd and Tom Raftery are already noting a Feedburner spike as a result.
Interestingly, Darren Rowse notes that subscribers from Google Reader/Desktop/IG already heavily outnumber the established and popular Bloglines reader.
Looking forward, one feature I would really like to see in Google Reader is feed discovery and recommendations based on readers with common interests and similar reading lists.