I am a developer-tier member of ADN. I started writing something this week but I’m not really sure where I want to go with the concept.
It’s not a Twitter clone, it’s more a social media platform, and there are amazing clients already. I use Felix, Kiwi, Riposte and Netbot.
So instead, I recommend you give it a look, now that it has a free (but limited) tier, and let me know what I should build.
My profile is here.