You can use trade these in for Love Tokens at a 1:1 conversion rate during the Love is in the Air holiday.
They are acquired by killing mobs when when you kill mobs with a Lovely Charm Collector's Kit in your inventory and collecting Lovely Charms and combining every ten of them into a bracelet.
Although the Lovely Charms and Love Tokens are Bind-on-Pickup, these braclets are not and can be traded. However, this year they can no longer be listed on the auction house or mailed due to being a "limited duration" item.
Good Lovely Charm farmspot for Love Token currency in WoD is at Shadowmoon Valley 37,22 underground, Carnivorous Squirrel. Location video: http://youtu.be/xFxHTwzeI7A