You know it's funny. Most people actually think people interview them because they want to see if they're right for the job on the "technical" level. No, if someone is interviewing you it's because they do think you might be right for the job technically but they want to see if you're an idiot or not and *know how to communicate* and work with other people without ******* them off.
If you're an interviewee, you better make sure you can communicate efficiently in these or else in my book, you lose major points. If the interviewer is a very good communicator and the interviewee can't keep the conversation, then that is bad in my book.
It's a two edged sword though really. If the interviewer sucks at communicating, I hope they don't really grade the interviewee down if they don't show strong communication skills. There's nothing worse than having a manager who can't communicate. Three years ago I had a manager who was one of the most aloof managers of all time. This guy, you'd try and have a normal conversation and his demeanor just sucked. Year end reviews say "You need to work on your communication skills." I go to a new manager, every year "Outstanding communications skills." You tell them about it and they say "you have to be kidding me...."
So keep in mind, it's not one sided but unfortunately interviewers are usually too stupid to realize they can create or destroy spontaneity of conversation.