Symphony.

Hello,

I want to be able to show author's twitter id in my post, like "Posted by Author Name @twitter-id". Is there a way to extend author essentials to include custom details like "twitter profile, website, bio, signature, etc? Would be nice if you could add fields to it.

Rather then extending the author's field, you could try and just make a section specifically for this task and add their details in there. That way you could also make a datasource from it and manipulate it as desired.