When to use LDAP over a database?

Question

When should I use LDAP vs. database/key-value-store/column-oriented-database/etc?

Answer 1

Here's the difference between the two: LDAP is highly optomized for reads, it can do them much faster than your MySQL database can, so it will scale much better than your database solution will in the long run which is optomized for reads and writes.

I'm sure that you will find more applications support LDAP for an authentication method than MySQL, and you will be able to integrate more into your directory. I would caution that before you go head first into LDAP that you take a look at the management tools for your particular LDAP implementation. OpenLDAP is great, but modifying the directory by hand all the time sucks.