I have studied the whole history of philosophy and never found any reference to love. Philosophers have debated on everything, even the angels dancing on a pin, is there really no attempt to define, discuss and analyze this subject?
For a wide historical conspectus you could check out Irving Singer:
The Nature of Love Volume 1: Plato to Luther (1984) ISBN 978-0262512725 The Nature of Love Volume 2: Courtly and Romantic (1984) ISBN 9780262512732 The Nature of Love Volume 3: The Modern World (1987) ISBN 978-0262512749
Names out of philosophy's historical hat:
Augustine ('Love, and do what you will' - Dilige et quod vis fac), Thomas Aquinas, Marsilio Ficino, Freud (honorary philosopher), and Max Scheler. More recent work includes:
Armstrong, John, The Conditions of Love: The Philosophy of Intimacy, Penguin: 2002. ISBN 10: 0713994738 / ISBN 13: 9780713994735.
May, Simon, Love: A History. Published by Yale University Press 10/05/2011, 2011. ISBN 10: 0300118309 / ISBN 13: 9780300118308.
May is more difficult that Armstrong but both are philosophers, not historians. An older book which still retains a good deal of value is:
Nygren, A., Eros and Agape, 2 vols, 1932. I should also mention:
Lewis, C.S., The Four Loves, Published by HarperCollins, 2002. ISBN 10: 0006280897 / ISBN 13: 9780006280897.
Empedocles wrote that there are six basic realities of the cosmos; each a genuine being in the Parmenidean sense. The four roots, as Empedocles referred to them: Earth, Air, Fire, and Water (later called elements by Aristotle), and two forces, Love and Strife. The roots are mixed and separated by Love and Strife to produce the world that we sense.
For example, from the Strasbourg papyrus (recently identified as the work of Empedocles):
I will tell a double story. For at one time they grew to be only one out of many,
but at another they grew apart to be many out of one:
fire and water and earth and the immense height of air,
and deadly Strife apart from them, equal in all directions
and Love among them, equal in length and breadth.
Behold her with your mind, and do not sit with your eyes staring in amazement,
She is also recognised as innate in mortal limbs.
Through her they have kindly thoughts and do peaceful deeds...
Of course! Where do you think the word "Platonic" comes from? Platonic love is named after Plato, who wrote extensively on the topic, as have, of course, many philosophers since.
Philosophers have examined every major topic they could think of -- that's what they do. Philosophy about Instagram is obviously still very young, but you'd have to try pretty hard to find a topic no philosopher has examined, discussed, or written a book about.