If the iPhone and Twitter go together like chocolate and peanut butter, then for the most part current iPhone Twitter client developers give us many variations of the peanut butter cup. Tasty confections though they may be, and each unique and delicious in their own right, at the end they still tend towards variations of the peanut butter cup.
Enter Reportage from wherecloud [$2.99 - iTunes link], which rearranges those twin flavors like nouveau cuisine, utterly deconstructed and left for you to explore.
Too obscure? Okay, rewind. Reportage bills itself as a "radio tuner" for Twitter where followers are treated like stations on the FM dial and you can tune in (or tune out) to what they're saying, and spin the dial to move from user "station" to user "station".
It should be noted at the beginning that Reportage isn't a general purpose Twitter workhouse. There are tons of those already. Like Birdhouse, which models itself on a "notebook" writing experience for Twitter, Reportage has also chosen to focus on one specific concept -- pseudo-"live broadcast" of the Twitter users you follow.
Keep that in mind as we go along...