I don't think it is a definite signal. It really depends on the personality of the interviewer.;D But I guess sometimes you can sense positive information if they do reply your thank you letters. Up till now, all my interviewers replied to my thank you letters. They simply replied something like "I enjoyed our conversation too" or "we'll get in touch shortly". I guess it might just be a way of manner.
I don't think it is a definite signal. It really depends on the personality of the interviewer.;D But I guess sometimes you can sense positive information if they do reply your thank you letters. Up till now, all my interviewers replied to my thank you letters. They simply replied something like "I enjoyed our conversation too" or "we'll get in touch shortly". I guess it might just be a way of manner.