Lowercase "l" looks sorta like a 1, so Europeans ( who are infinitely smarter than Americans ) add a little tail to the top of the 1. Now the 1 looks like a 7. Oh shit! So then they add a crossbar to the middle of the 7, which now looks like a Z, so then they add a tail to the bottom of the Z, which now looks like a backwards E, which confuses the Russians, and the whole damned thing just keeps going on and on and on... Its use is explicitly forbidden by the Japanese, who are apparently much smarter than us, until one realizes that they speak Engrish.
L is the international symbol for lesbianism. Good quality lesbian porn gets a triple ( 'LLL' ) billing.
The letter L has alse been believed to symbolize some kind of reference to NEDM, thouch none has been proved.
L on the internet
The lowercase 'l' can be used as a quick and easy substitute for an uppercase 'I' in MSN conversations, as when using the default font both characters are identical, doing so results in the user seeming almost semiliterate, except for the small fact that they are using MSN in the first place.
L also has an evil twin brother, named "Ł".