Idea for my next iPhone App: Duplicates in your Address Book

My Tax App “SmarterSteuer” has been in the iTunes App Store for almost a month now. Of course, the sales are not even remotely close to allow me to quit my day job – at 1.59€ and about 25 sold apps I haven’t even recovered the cost for my membership in the Apple development program. Nonetheless, I’ve been impressed with the number of sales and the pretty level number of sales from day to day: The tax app is quite limited to a certain type of user (freelancers that have recently started and are trying to figure out their taxes) and it’s only applicable to Germany (and it’s only available in the German App Store). I’ve been trying to guesstimate the market size for a general purpose app that would be sold worldwide.

Guessing a Market Size

I’ve been trying to find out how many iPhones have been sold worldwide and in Germany. Apparently, Apple releases quarterly numbers (compiled in a nice sales graph by wikipedia) which would put the number of iPhone sales worldwide to about 90 million at the end of 2010. I couldn’t find any matching numbers for Germany, the latest number I could find was 1.5 million at the end of 2009 where the worldwide number was at about 40 million. That would put the worldwide market at about 27 times the German market which is consistent with a 4% market share that admob is estimating for Germany. Let’s work with a nice round factor of 25. 

It’s even trickier to estimate what part of the current German market would consist of freelancers. In the general German population you have roughly 1 million of freelancers (with 81 million Germans total). I’m assuming that that percentage would be mich higher among the owners of an iPhone. Just for arguments sake, I’m working with a percentage of 10% of freelancers in the whole iPhone market in Germany.

If we take these two numbers, we come up with a factor of 250 – i.e. the market size of a general purpose worldwide app is about 250 times as large as the market that I’m currently addressing with my text app. This may not translate to 250 times as many sales or 250 times the revenue, but even 100 times the sale of my current app would be quite impressive.

I’m not sure how if these numbers are reasonable (please let me know if you have better numbers or estimates) – but it’s certainly encouraging enough to contemplate writing a general purpose app that can be used worldwide.

App Idea

I’ve got a few ideas that come close to the description of a general purpose app with a worldwide appeal, but the one that fits best is an app that analyzes the iPhone’s Address Book and looks for duplicates (either created because of synching problems or by manually entering the same person twice). So here is a short description of that idea:

Level 1:

  • look in your address book for potential duplicates
  • visualize the “duplication” in a nice way so the user has a chance to follow up on the results by manually editing/deleting the records

Level 2:

  • offer a way to “automagically” delete complete duplicates (i.e. record identical in all fields)
  • offer a way to merge records (i.e. if the names are the same but each address is different create a record with both addresses so the user can manually edit the “survivor”)

Level 3:

  • add-on services such as address validation or other ideas that come up in the meantime

I think that this may be a valuable app, something that people are willing to pay for. I’m not sure about the effort required to develop such an app, but I’m ready to start. Most of the technology should be pretty straightforward (accessing the address book, comparing records/strings etc.). I’m going to mull this over for a few more days, but I think I’ll get started as soon as I have some time available.


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