Venus is considered to be Goddess of love and in Hinduism it's considered to represent Guru of demons. Venus enters in its exaltation sign on February 3rd this year, which makes it to be in its exaltation sign even on the Valentine's day. It does not happen every year though. For example: Venus was transiting sign Sagittarius in 2011 on Valentine's day.It was in its exaltation sign in 2007 too on the Valentine's day.
The time of transit through one sign for Venus is almost one month but it is because of its retrograde motion that it takes slightly longer to move through one sign at times and hence the irregular patterns of its being found in the exaltation sign Pisces at the time of Valentine's day. Venus finds itself most powerful in the sign of Pisces. Though Pisces is owned by its enemy Jupiter, it is a dual watery sign signifying dreams, imagery and fancies and here Muse feels most comfortable and powerful. Persons who have exalted Venus in their charts are very attractive and they possess magnetic voice. If in a Kendra house it might suggest extraordinary powers of imagination and high libido.