Slideshare's UI guys are really rather good.
Every now and then, you come cross a piece interaction design that's so well executed, it'd be plain disrespectful not to write about it. Today, I had one of those moments on Slideshare.
I wanted to favourite this presentation by Drew Houston, Dropbox Startup Lessons Learned, about how they applied lean startup principles internally at Dropbox, so I signed in to the site.
From there, I was 'upsold' into tagging the content (useful for me, but also useful for the site)
From there, I had already switched from being a passive consumer, to being an annotator, and from there it wasn't much of a jump to convert (note the deft use of clever micro-copy) to being a commenter, adding what (I hope) was some extra value to the page an increasing my engagement with the service.
Each step seemed natural, and unforced.
Wow, these guys are good.