Interleaf is a dedicated reader app that syncs with the "dashboards" of social-networking websites like Tumblr and Twitter, splitting them back into the "feeds" they're made from, and then giving you a view into those feeds that resembles an RSS reader.

Resembling an RSS reader means:

• Interleaf's items will stick around until you've marked them as read.
• You can start reading from the oldest thing you've missed, rather than starting "at the top."
• You can read a unified stream of everything, or you can just catch up the items from one blog. Either way, those posts will get marked as read and you won't have to scroll by them again.
• Interleaf only expands one post at a time. Your computer will thank you for all the GIFs and videos that aren't open and playing in the background.

Beyond this, Interleaf also has some features RSS readers don't have, because Interleaf understands that the feeds it's managing are all connected in a single social graph.

• Interleaf won't show you the same post over and over. If 50 of your friends share the same cat photo with you, you'll just see it the first time, with all 50 notes attached.
• Taking this further, Interleaf has a conversation view you can toggle on and off. In conversation view, all the "reblogs" or "retweets" stemming from the same "root" post will be condensed into one long post. When people throw in their two cents, that conversation thread will get bumped to the top, with the new messages expanded and the previously-read messages collapsed. You can mute a conversation at any time, and it will be like everyone involved suddenly decided to STFU. Joyous.

Interleaf also has its own servers, to store stuff the social networks don't have a place for. This means:

• Interleaf, like an RSS web client, will keep track of your "unread" (and more importantly, "read") items, regardless of when or where or on what device you read them. Interleaf will also keep track of the posts you've reblogged/retweeted, so you can avoid annoying your followers with The Same Picture of Dave Coulier Every Day.

• Interleaf's server watches your feed even when you have the app closed, capturing a copy of each post as it's posted, and keeping them even if the original posts later get deleted. Many people delete certain posts from their blogs soon after making them, just to tidy up; these posts will appear greyed out in Interleaf, but are still readable and even shareable. (Any blog author who is given the heebies by this should add the NOARCHIVE meta attribute to the theme of their blog, and we'll respect that and remove all their deleted posts For Real. Remember to do the same for the Internet Wayback Machine, or they'll archive your blog's website!)

• Interleaf has its own queue, separate from any queue your social network account might have. This queue isn't for your own Original Content; instead, it's to hold the ridiculous amount of reblogs/retweets some people like to make, and pace them out. Things you reblog/retweet through Interleaf automatically go into Interleaf's queue; the queue is smart enough to post them right away if you haven't posted anything recently, or to stagger posts like you'd expect if you're on a sharing spree.

• Speaking of reblogs/retweets, Interleaf lets you automatically share the things you ♥ onto their own blog(s). In fact, there's no explicit reblog/retweet button in Interleaf; instead, Interleaf guesses (and learns~!) which of your blogs you'd share a given post to, and makes the ♥ button into a "♥ and reblog to [blog]" button. (Which has a dropdown to correct bad guesses, and a 30-second undo window before posts Actually Happen, in case you still managed to send a He-Man picture to your work blog.)

• Interleaf downloads big GIF images in posts to its servers, and turns them into GIFVs/WEBMs for the Interleaf client. Because watching with agonizing slowness as each frame of a cat-encountering-a-cucumber GIF ticks by is ridiculous.