• by Gavin O'Malley  @mp_gavin, June 10, 2015

Appealing to advertisers’ boundless passion for targeting, Twitter is now letting app advertisers reach users based on the categories of apps already installed on their mobile devices.

“One of the biggest priorities for mobile app marketers is to reach the people who are most likely to use and love their apps,” Deepak Rao, product manager of revenue at Twitter, writes in a new blog post.

“With installed app category targeting, you can identify new audiences of high-quality users to target within your existing app category and in related app categories.”

Advertisers can also combine the new feature with other targeting types, including keyword, language and location targeting.

“For example, an advertiser that wants to drive installs of a task management app can select the ‘Productivity’ category to reach users who have recently installed similar apps,” according to Rao. “That same advertiser may know that productivity app users also tend to use finance apps, so they can target the 'Finance' category to connect with new people who are likely to be interested in their app.”

Twitter is also releasing new reporting and analytics for installed app categories within the advertiser dashboard. The reports are available for all mobile app promotion campaigns, whether or not those campaigns used installed app category targeting.

As part of a broader “app graph” initiative, Twitter began tracking the various other apps that consumers have on their mobile devices, late last year. Users who are uninterested in such a “tailored experience,” as Twitter calls it, can opt out by adjusting the Twitter app’s settings.

Also, Twitter has promised not to keep tabs on users’ app information if they have previously opted out of “interest-based” ads by turning on “Limit Ad Tracking” on their iOS device, or by adjusting their Android device settings to “Opt out of interest-based ads.”

Facebook also collects data on some of the other apps that users have on their mobile devices.