Under certain circumstances using LDAP as a directory or data-store and not just for authentication alone can make sense, especially if you want to benefit from the very well standardized, open and stable interface or if some sort of multi-master scenario is needed or if you want very rigid control over who can see what portion of the data then the most popular LDAP servers offer a lot of very cool ways of "modelling" and managing your data.
One drawback to keep in mind is that LDAP is generally not meant for lots and lots of writes so it is by no means a substitute for DBs but it is great for looking up data and if that data somehow fits a sort-of "file card" paradigm anyway and there are way more reads than writes on that data and several different applications should be able to access it then all the better.
The major and most popular applications of LDAP, however, are certainly always somehow connected to authenticating users and that is also where it really, really shines and that was another reason I brought it up. If applicable, personally I would prefer managing users and their logins in an LDAP server over keeping all that in a database.
Luckily nowadays most (web) applications offer some sort of support for using LDAP anyway, however dodgy those implementations sometimes are. (One of my favorite examples here is netscape navigator/mozilla/thunderbird and the addressbook schema shenanigans...)
I just think it gets too little credit or news these days but that probably stems from the fact that it is a pretty stable system without lots of innovations and it has been around a looong time and it is not so "sexy" anymore and most HN hackers wouldn't have to deal with it most of the time anyway.
But I cannot recommend looking into LDAP and playing around with it and understanding how to get a directory going enough - it is a bit confusing (sometimes frustrating) at first because it is so different from typical databases but it is fun once you get the hang of it and learn to appreciate its simple and efficient beauty and some of the things you can do in huge directories with e.g. the Sun LDAP server are nothing short of amazing.
I worked with LDAP servers for a few years, but never liked it much. Perhaps I missed something. What can you do in huge directories that is so amazing?
One drawback to keep in mind is that LDAP is generally not meant for lots and lots of writes so it is by no means a substitute for DBs but it is great for looking up data and if that data somehow fits a sort-of "file card" paradigm anyway and there are way more reads than writes on that data and several different applications should be able to access it then all the better.
The major and most popular applications of LDAP, however, are certainly always somehow connected to authenticating users and that is also where it really, really shines and that was another reason I brought it up. If applicable, personally I would prefer managing users and their logins in an LDAP server over keeping all that in a database.
Luckily nowadays most (web) applications offer some sort of support for using LDAP anyway, however dodgy those implementations sometimes are. (One of my favorite examples here is netscape navigator/mozilla/thunderbird and the addressbook schema shenanigans...)
I just think it gets too little credit or news these days but that probably stems from the fact that it is a pretty stable system without lots of innovations and it has been around a looong time and it is not so "sexy" anymore and most HN hackers wouldn't have to deal with it most of the time anyway.
But I cannot recommend looking into LDAP and playing around with it and understanding how to get a directory going enough - it is a bit confusing (sometimes frustrating) at first because it is so different from typical databases but it is fun once you get the hang of it and learn to appreciate its simple and efficient beauty and some of the things you can do in huge directories with e.g. the Sun LDAP server are nothing short of amazing.