Noel Tyl refers to it as 'peregrination', not making major aspects. He wrote an interesting article about it and refers to it in his 'Vocations' (good book).
CONSPICUOUS BY ABSCENCE
As 'peregrination' is a term used in horary, I prefer to use 'calling' (drawing attention). What I call 'calling planets' are planets not making major aspects in sign. I have written about it on my site Astromarkt, in the article'Conspicuous by abscence...', that is also about missing elements.
A CALL FOR...
In short: 'calling' planets manifest themselves at any level, but always intense. A calling Mercury just HAS to communicate and a calling Jupiter just HAS to convince or travel. It is a sort of an urge. People with 'calling' planets should not disregard their influence and try to give the planet a place in the field of the carreer or in their hobbies. Or else, this planet starts 'screaming'!:) And the calling Mercury will never stop talking, the calling Jupiter will be anoying all company with statements and the calling Uranus will be irritating and shocking whenever there is a chance.
I tend to see the 'calling' planet as an indication for a vocation. A calling Sun (like in the charts of John F. Kennedy, Nelson Mandela, Hillary Clinton and Cher Bono Allman, for example) refers to either leadership or show (being the centre of attention). Or how about the calling Venus and Mars of Monica Lewinsky: the passion and male-female contact in her life caused a lot of noise:)!