Love-in-idleness is a folk name for a European herb from which pansies are derived.
It is also known as Jack-jump-up-and-kiss-me, heart's-ease, cuddle me, kiss-her-in-the-buttery, and meet-me-in-the-entry.
Across Europe it probably has dozens of other local names.
I came across it in Edward Thomas's 1917 poem Lob, but Shakespeare mentions it in Midsummer Night's Dream and before that it's in A New Herball, or Historie of Plants: Wherein is contained the whole discourse and perfect description of all sorts of Herbes and Plants, here.
In contrast to such poetic names for a common flower, the names of the popular del.icio.us tags are functional and boring.
Why? (And this isn't a criticism of del.icio.us)
Maybe because folk names like love-in-idleness are local, whereas del.icio.us tags are global?