tags:

views:

261

answers:

5

For example, "a2xki"

+4  A: 

Why don't you Ask Reddit?

Jeffrey Hulten
A: 

Because you can represent it with [a-z0-9], most likely.

Just Some Guy
+6  A: 

Probably because:

Base 36 is therefore the most compact case-insensitive alphanumeric numeral system using ASCII characters

Ben
+1  A: 

Second Just Some Guy (you can represent with [a-z0-9]), Also,

  1. This scheme should produce very short IDs.
  2. Easy to use these IDs to create on disk structure.
  3. Easy to convert to numeric IDs to look up database, etc.
grokus
+1  A: 

It's easy to give to others in email, verbally, chat windows, etc. The URL would certainly allow more characters, but this is less confusing, especially if you have to read the link over the phone, in a video, on TV, or even typing it in from a printed article or newspaper.

It's very human friendly.

Adam Davis
why not number??
fenglanchi
It is a number, in base 36. Why base 36? Because 0..9 + a..z = 36 characters.
Jeffrey Hulten
I think there is quite a bit of added value in base 36 for the recognizability of the id. Instead of looking like another number, which isn't as recognizable, it looks like a (very unique) word, and thus easier to remember. 2342354 vs. as57q (numbers non-randomly chosen for effect)
Tchalvak
It's not a number because base 36 is shorter for the same ID. A 4 digit base10 number can only represent 10,000 articles while a 4 digit base36 number can represent 1,679,616 articles, and still be just as readable/printable/usable.
Adam Davis