How do you recognize kindred energy when you meet someone (esp. online as we do here on HP)?

as with a current discussion in the forums, it's a recognition based on a gut feeling, or intuition. or the inner voice.

By how my heart Chakra reacts. If my heart opens and I feel happy and balanced when reading their words, looking at their pictures or listening to them via video, I can usually tell if their energy is in the same vibratory range as mine.