Until recently, I didn't understand the fascination many people have for collecting signatures from celebrities, politicians and other well known people.  When I recently attended an event at the Hindu temple here in Northern Virginia, I saw a short film that made me change my mind.  In this film, some form of Kirlian photography , or something similar to it, was used to photograph the energy fields around a small table with a signed letter on it.  When the letter was written by an average person, the energy fields around the table were mostly in colors that the narrator said indicated negative energy.  There was just a small area of green positive energy around the letter.  When the letter was written by a Hindu saint or holy man, the area of green above the letter was about ten times as large.  So maybe having a letter written by, or signed by, a holy person does have some benefit.  
    The film didn't go into what would happen if the letter written by the saint was handled by a number or average people, but I think it would probably loose it's positive energy over time.  Just as former holy places loose much of their positive energy after thousands of  non-spiritual tourists visit them.