Love letters express the unexpressible emotions between two individuals. Writing and/or receiving a love letter from a significant letter accentuates the love felt between the two parties involved in the relationship. A glorious feeling, the purpose changes as the relationship evolves. It can all start in the first few months, but its when the letters continue to flood your mailbox/email account that the true feelings are exposed. You become closer with this other person, and feelings evolve... hence do the letters.
I typically hold-on to all of the letters I have received from Prince Charming. When he may travel for business, and I am missing him dearly, I pull out those letters and re-read his thoughts and emotions. It is quite overwhelming, but if read in succession... I can prove my point regarding the evolution of the relationship.
Overall, I believe the art of writing/receiving love letters can keep a relationship alive.
Here is the definition from Wikipedia:
Love letter: From Wikipedia, the free encyclopedia
A love letter (French: billet doux) is a popular way to express feelings of love in written form. Sometimes sent in the mail, and increasingly by electronic mail, the letter may be anything from a short and simple message of love to a lengthy explanation of feelings.
Sometimes letters are preferable to face-to-face contact because they can be written as the thoughts come to the author. This may allow feelings to be more easily expressed than if the writer were in the beloved's presence. Further, expressing strong emotional feelings to paper or some other permanent form can be an expression within itself of desire and the importance of the beloved and the lover's emotions. The expression of feelings may be made to an existing love or in the hope of establishing a new relationship. The increasing rarity and consequent emotional charm of personal mail may also serve to emphasize the emotional importance of the message.
As with any letter, a love letter could be written in any structure or style. One historically popular method is as a sonnet or other form of poem. William Shakespeare's sonnets are often cited as good examples of how to write emotional themes. There have been published books collecting models and suggestions for love letters.
After the end of a relationship, returning love letters to the sender or burning them can symbolise the hurt felt.
Some stationery companies produce paper and envelopes specifically for love letters. Some of these are scented, though some people like to use their own perfume to strengthen the impact of the letter.
I personally hope to continue to receive these loving letters, well into my days... I dream to be a wrinkly old bag and still getting excited to read a letter from my love.