I have to confess that I haven't looked at the link given earlier - but I will!!

Border Collies were recognised as a breed in this country around the middle of the 18th centuary. It came from the Border country between Scotland and England, prime sheep country. The breed had been around for a lot longer than that. They were bred for their intelligience, fast actions, herding instinct, endurance, and willingness to learn. The dogs true to the breed are constantly ready to go, always open to training if the handler is the right one and impossible to tire! Just when you think they can take no more, ask them to do something else and they can!
We tried them as Guide dogs but found them too fast for most owners, even crosses. They are also liable to sound shyness under any sress.
The true dog is an uncomfortable house mate unless his mental and physical needs are catered for. A bored collie will be a destructive collie. Either to himself or, more commonly, his environment. This is not a breed to take on lightly.
The UK kennel club was petitioned some years ago to seperate the breed into two, or preferably three, classes: the working collie, the show collie and the pet colie.
This shows the variation within the breed, but nearly all are extreme in their need for mental and physical stimulation, at the same time if possible. The mental stimulation is the part that most owners struggle with. This is a loyal, clever dog that will be your best friend if you treat it properly. That is not to say that you can't work and have collies - you just have to put them before everything else when you get home! Obedience was made for these dogs as was agility and flyball and, if you work, these activities could save your sanity!
Border Collies should be bred to be fairly dominant - they won't handle sheep if they're not- so you need to be a pretty savvy owner to give the dog a life that is equal to it's abilities.
Not for everyone, but if you have the time and energy to teach you have a sponge as a pupil!