Firefox' handling of RSS feeds as live bookmarks was one of its killer features back in the day, at least to me. But it must have hit a nerve with others, too, because I remember that Microsoft put something RSS-related into IE7; I never used IE7, though, so I cannot vouch for that.

Of course, there are alternatives, but still - the live bookmarks are really cool and extremely convenient to use. It's a shame they are going to be excised. At least that gives me an incentive to pick up the RSS aggregator I wrote a couple of years back and polish it a little.