RSS "pushes" website updates to readers around the world so they don't have to find them through search or refreshing the site. It was a game changer when it evolved into popular use in 2005 — not coincidentally around the same time Ask.com acquired Bloglines from its founder Mark Fletcher — but social sites of all types from Twitter to StumbleUpon to Digg to Facebook have all but replaced it for most users.
While some users still follow their favorite websites on Facebook or Twitter, many people simply rely on their friends and other contacts to share and suggest interesting news on social networks.
"RSS aggregator usage has slowed significantly," an Ask.com rep said in a blog post yesterday. "Bloglines isn’t the only service to feel the impact. The writing is on the wall. "
Since Bloglines will remain operational until October, you have about three weeks to export your feeds to another RSS application such as Google Reader. The folks behind the scenes at Google Reader have added social features to that app to try and combat RSS's reduced prominence.