Was searching for the reason why retro bikes have forks that curve forward and come across this thing called the fork rake. After reading through a few articles, I found them a little confusing and hopes my post here can help folks looking for quick answer pick up knowledge faster. (Those who knew need not read further of course!)
Forks are made to curve forward to create rake. The further it curves out, thus bringing the hub further away from the steering axis, the more rake.
Rake results in the front wheel contact point on the road to get nearer to the pivot. Distance between the contact point and the pivot is known as the trail. The more rake, the less trail.
Without rake, the front wheel is like the shopping cart wheel with castor, eager to point forward and more stable for cruising, and long distance ride. However, trail has a disadvantage, it is less responsive to steering input, making the bike less agile when making quick and abrupt turns on busy streets.
Quick recap: Rake = agility. No rake = stability.