Why I use UUIDs for primary/foreign keys

[eluser]n0xie[/eluser]
Random 5 reasons we use integers:
1. Performance (joins/ indexing)
2. Size (just how big are your tables?!?!)
3. Int is a native data type, therefor faster with any form of computation. It's much easier to validate/sanitize if it is passed from an URL making SQL injection much easier to prevent. Santizing strings is like a box of chocolates: you'll never know what you're getting.
4. Readability. Where id = 123 vs id = '{BAE7DF4-DDF-3RG-5TY3E3RF456AS10}'. Also if the id is the primairy key and auto incremented it gives you as a developer an indication when it was inserted. Sort by id DESC to see the last few entries. Try that with GUID.
5. Usability: http://domain.tld/blog/123 vs http://domain.tld/blog/BAE7DF4-DDF-3RG-5TY3E3RF456AS10. 'Clever' users will know that the next blog item will be 124 and the previous blog item will be 122. As for GUID...