At the turn of the century in England, milk was delivered in open glass bottles. There were 2 birds that loved to drink the cream that would settle at the top of the milk. These were the Blue Tits and the Robins.
Then after world war 1, milk was delivered still in bottles, but with an aluminum top to prevent the milk from spoiling.
This also prevented the birds from drinking the cream. At least temporarily. You see, the blue tit learned how to peck through the aluminium foil, where as the Robin did not. Throughout England, Blue Tits would get the cream, but Robins could not figure it out. Now you would probably think that Robins are not as intelligent as Blue Tits, which is why they could not get to the cream, but this isn’t the case.
Robins are territorial birds. They come together when mating, but then quickly stay on their own in their own territory driving off other Robins. This means that they do not get a chance to share knowledge. Whereas Blue Tits are social birds, when one bird figures something out, it is shared among other birds. So if one bird figured out you peck through the aluminium foil to get the cream, soon all birds would know. For a Robin, if one bird figured out how to get to the cream, only that bird would know. The group misses out.
The same can be said with Humans. Those that hoard knowledge may be smart on their own, but the overall system looses out. Whereas those that share knowledge as a group, all benefit and get better.
The same goes for anyone who defends their territory (Those unwilling to learn from others) will also miss out on gained knowledge.

We can see this play out socially at the moment in Facebook. A mother shared how she removes splinters using a syringe by usig suction instead of jabbing her children with a needle to fish the splinter out. This simple tip has made it across the world and is being shared by news organisations, newspapers etc. It just shows how infectious learning is.

So share your knowledge. Write blogs, do talks, not only within your own team, your own company but with all who will listen. In the long run, we all benefit.