Effect

The Mentalist takes the phone from a spectator and announces that he has to make a search in a social network. Once its done the mentalist leave the phone on the table
The mentalist asks to the spectator that imaginge that is on twitter and want that imagine to himself seeking or publising something in twitter. EThe spectator says for example that has imagine seeking the Talman profile or that it would like to read the latest Harry Potter book

Under these conditions, the mentalist ask the spectator to take his mobile phone and look which was the search done
Believe it or not, the spectator when he take again his mobile will find the asked search done on twitter. E
Likewise you can predict profiles on google plus or Linkedin.