I’ve been using a free iPhone app called Nuzzel to catch up on interesting links and news shared on Twitter following a recommendation on Kottke and a tweet by Ben Thompson. I’m a fan of the underlying idea and the execution of filters in the app, but there are a few things that annoy me and that, I suppose, stem from this startup’s need to track clicks on links and “user behaviors” as much as possible.

Nuzzel aggregates links shared by people you follow on Twitter over a specific period of time. Tweets containing the same link shared by multiple people are coalesced into a single article recommendation in the app, which displays the title, a brief excerpt, the source, and a count with the number of “friends” who shared the story alongside their profile pictures. The useful aspect of this is the way Nuzzel lets you adjust time filters: you can find the most shared links for the past 1-8 hours, the past day, a specific day in past week, or links from last week. By hitting the date button in the upper right corner, you can change the date filter at any time and “travel back” into, say, Twitter from two days ago and see what your timeline was talking about without scrolling long lists of tweets.

I started using Nuzzel when I was on vacation earlier this month, and its time-shifting functionality came in handy because I needed a way to quickly catch up on the news without the effort of scrolling my timeline. For me, the best way to discover links is to trust people I follow that what they’re recommending is worth of my attention, and Nuzzel is built around that concept in a clever way.

The app’s filters can also be approached from another perspective – rather than past links, recent ones shared by a specific number of people. You can choose to view all recent links shared by all friends (which sort of turns Nuzzel into a read-only, link-only Twitter app), or you can view stories shared by 2 up to 10+ friends, which, again, will aggregate tweets, displaying a single link with a friend count.

There are other sections you can check out in the app’s sidebar, such as “news from friends of friends” and featured feeds. I’m not interested in browsing popular people’s feeds or seeing links from people I’m not following, but I like the two other additions to the sidebar: recently read stories and news you may have missed. The former is a recap of links you’ve opened and read in the app, while the latter is a list of popular stories that you may consider reading. I’m not sure how Nuzzel aggregates stories in this section or whether they’re recommended based on user taste, but they’ve been fairly interesting in my tests.

My problem with Nuzzel is how it puts a frame around links with a “social bar” that contains buttons to share stories and other recommendations. On mobile, you don’t see the social bar, but it’s there on desktop devices, with a nuzzel.com URL wrapping the link. It reminds me of the old Digg and StumbleUpon, and I thought we were done with this stuff.

Furthermore, when you share a story on the iPhone the app returns a short URL, which can’t be cleaned up with my old method as it’s a full frame around the original webpage. When I tried to copy a link from the iPhone app and save it to Instapaper, it couldn’t be saved because Instapaper couldn’t reach the original page. To my knowledge, the only way to save links to Instapaper and get the original link is to tap & hold a story and either save it or open it in Safari, from where you’ll be able to copy the original URL. I suppose Nuzzel is forcing these frames and custom URLs to better track the behavior and reading patterns of users, which, I guess, may also help the “People who liked this story also liked…” section in the app.

Nuzzel’s basic feature – reading news on Twitter with time filters – has been useful to me, but I wish the service didn’t rely on frames and custom URLs so much. I don’t know how the company will “monetize” the service or what other plans they have for the app. Right now, Nuzzel is a handy utility to find links on Twitter, it could use an iPad version, and it’s free on the App Store.