I'm intrigued by apps that try to augment or replace the built-in apps in iOS. Apple's done a fine job with core functions like calendaring and contact management, but there's so much information stored in so many places these apps don't reach, like social networks, it seems like somebody should be able to offer an app that collates it all in one place.

The latest app to try it is Humin, which proposes to replace both the iOS contact manager and phone calling app. It got a nice writeup on Business Insider earlier this week, so I gave it a spin. I downloaded it for free, connected it to my Contacts and Calendar app, to Facebook, and to my Gmail and Exchange (work) email accounts. 

Sure enough, it's pretty. The app scours Facebook to provide little square images of all your contacts -- sort of like the People app built into Windows Phone, which I love -- and there's a cool swiping function that lets you call or text any of them from within the app (swipe left to text, which opens iMessage; swipe right to call, which happens without ever leaving the app). 

But the real strength is the search function. If you can't quite remember the name of that person you met at a conference last year and exchanged a few emails with, you can run a search like "met last year, lives in Miami" and it should theoretically find the right person. (In this way, it's a little like Refresh, which uses info from your social networks to give you a quick rundown of people you're about to meet with.) 

In fact, searching is the only way you can navigate Humin -- there's no alphabetical list of contacts, although you can pin a few favorite contacts to a faves list.

I was so excited about its potential, I actually dragged it into the bottom tray of my iPhone to replace the built-in phone app, and relegated my Contacts app to the third page of apps.

Until this morning.

Yesterday, I caught up with an old colleague, who gave me her new business card. I entered her new email address into Humin and deleted the old ones, which were no longer valid.

Then, this morning I opened the old Contacts app to see if the changes had carried through. I wanted this information to be accurate because I still planned to use the built-in Mail app in iOS, and Mail auto-suggests email addresses based on the information in Contacts.

Nope. The old email addresses were still there.

So I went to delete the invalid addresses from Contacts, and the Contacts app crashed. It does this every time now on this particular person's contact information.

Yikes.

Then I went to Gmail -- the original store of information for this contact. Sure enough, the old invalid addresses were still in there.

In other words, changing the contact in Humin did not sync those changes back to the cloud services in which the information originally resided. Which meant the changes didn't propagate to any other app (like Contacts) that use this information.

That's the problem in a nutshell -- like so many other would-be contenders for placement on your phone's home screen, Humin wants to be the one. It syncs everything into the app, but once you've installed it, it expects you to do everything from it. If I wanted to use Humin to send email, there would have been no problem. As soon as I wanted to use another app, blotto.

There were also some problems with the search function -- for instance, this woman lives in New York, but Humin's headline says she lives in San Francisco (although her name still comes up when I search for "lives in New York"). Another person in my contact list lives in New York most of the time, but is living in San Francisco for a few months. Humin got that wrong as well. And the app is currently not able to sync with LinkedIn, which is a big store of important professional information for me.

Here's what I really want: A single master app that contains 100% accurate, up-to-date information about everybody I've ever called, texted, emailed, friended, LinkedInned (is that a word?), and followed on whatever other social network I'm using to follow people this week. Every time I change anything in that app, I want the changes to propagate to the cloud service where the information originally lived. Even better, when my contacts change their own information in any of these services, I want the app to update itself, then propagate those changes back all to the cloud stores where I have their information. 

Until this mythical arrives, I'll stick with the built-in iOS apps, and hope for the day that Microsoft releases the People app -- the closest to this ideal contact manager I've ever seen -- for iPhone.

Hey, the way Microsoft is embracing other platforms these days, it could happen.