How four mobile geeks in a room took on a six-million-dollar app discovery algorithm

Screenshot from Nov. 11, 2015: Hey there, WhatsApp! What’s shakin’, Facebook?

What we saw in the market

So we started poking around. “The app discovery problem” has been a buzzword on everybody’s lips for the last several years. A handful of proposed solutions have been legitimately interesting:

  • AppCrawlr: Crawls both App Store and Play Store for keywords to automatically classify apps based on tagging system. Detailed semantic search engine. Lots of false positives. No original content. Acquired by Softonic back in March; haven’t seen any updates since then.
  • Appbrain: Crawls Play Store and indexes apps for super-duper SEO power. No original content. Plummeting Alexa, but still gets plenty of wayward traffic. “Discovery” only in the sense that they frequently show up first on Google results.
  • Playboard: User-curated lists. Android only. Web and app based.
  • Ask a question (“What is the best cross-platform note taking app?”) and get answers from the community that can be up/downvoted, reddit-style.
  • XYO: An app and web-based classification system that crawled the stores and automatically assigned a wide variety of tags. It allowed you to browse “similar apps” based on the tags, plus provided snippets of user reviews that it detected as potentially relevant. No original content. Acquired by Mandalay Digital Group and disappeared.
Holy shit.

How to logically break down the dual oceans of apps

Our humble four-person Content team learned as much as we could based off of the marginal success of the competition. It’s a sticky problem, clearly. Right as we put it on our to-do, the big news in app discovery was the acquisition of AppCrawlr by Softonic to the tune of a cool $6M.

… oh god.

The app tagging process

We coordinated with the Appszoom Product folks to set up the skeleton taxonomy, which let us associate any number of tags with each app.

  • Editors: 4
  • Tags: 741
  • Apps per tag per platform: 10 minimum
  • Time to properly tag an app: Between 3–5 minutes. Requires familiarizing oneself with the app, scanning through list of hundreds of potential tags, validating tag update, checking for related apps (Pro/Lite versions, Android/iOS)
  • Estimated hours invested in initial tagging effort: ~1000. Half for the top downloads, half filling out the full taxonomy — and not including any of the countless meetings wherein we debated the respective merits of Air Traffic Tracker vs. Flight Tracker and what exactly qualifies as an Incremental Game.
  • Tagging start date: March 11, 2015
  • Celebration date of filled-in, cleaned-up taxonomy: August 6th, 2015
  • Number of tagging-related spreadsheets in Drive: 16
  • Apps tagged as of November 11, 2015: 19,234
Splashing it all over the homesite.

What’s next?

We’ve got a ton of ideas of where to go next with our fledgling taxonomy, some of them already being pushed into production.



Content designer. Sassy futurist. Ukulele plucker. Ottolenghi acolyte.

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Janel Torkington

Janel Torkington

Content designer. Sassy futurist. Ukulele plucker. Ottolenghi acolyte.