Explain PageRank to a five-year-old.

PageRank is Google’s algorithm to evaluate webpages depending on

• How relevant the page is to the search terms
• How many other pages link to it
  • Also takes into account the page’s own reputation

We’ll need to think of items or collections that are 5 year olds are familiar with.

• Books
• Toys
• Clothes etc

Let’s pick toys to explain because… well because toys are fun!

You’re Adam, a 5 year old.

You live in a neighborhood and have quite a friends who you play with. Each of you have a few toys but obviously you get bored playing with the same toys days after day.

You and your best friends Bunny and Chan come up with a brilliant idea. You decide that you will put up a notice board (search engine) in the playground that tells others kids who has which toys. That way you can all exchange each other’s toys and everybody has lot more fun.

But how you do it?

You go to each of the kids’ homes and ask them what toys they have. (indexing).
You get something like:

This is cool, but you realize that there are many kids in the neighborhood and the adjacent neighborhood (scale) and a lot of them have common toys. Not all of them are your friends. But they may be friends of friends. You know Faye, and Faye knows Kaya, and Kaya knows Nguyen etc.

So you and your friends (crawlers) split up the tasks and decide to do this cleverly this time. You:

• Meet your friends and ask them about their toys. (seed)
• Ask your friends about their friends and what toys they may have. (hyperlinks)
• You also ask which of their friends are nice and like sharing toys. (quality)
• You go to the friends and friends and repeat this process.

Finally you now have the details to build your notice board.

So if you’re Injani and you want Lego (search term), you see who has them:

Chan, Eddy, Goric and Monica.

But you can actually rank them now from how many other kids say they share toys.
So your results would be:
1. Eddy - 7
2. Monica - 3
3. Chan - 0
4. Goric - 0

That’s ToyRank/PageRank.