Letterboxd is a site to journal the movies you've watched or want to watch. Great design and obviously built by people who love movies.
I hadn't heard about an iOS app coming - but maybe they've talked about it on Twitter during my absence - but they dropped this tease in their recent email newsletter:
All the SXSW love we got for Letterboxd from both filmmakers and fans was encouraging and has us working harder than ever on the forthcoming Letterboxd app… because we know you want it, and we want to get it really right for you. We can tell you that we’ll be launching on iOS first, and below we’ve included a little peek at a couple of screens (no promises these won’t change before we ship though).
The site works ok on mobile but an app will definitely improve the experience.