It looks like Twitter has been testing out a new type of ad unit on mobile: promoted app installs. Circa co-founder Matt Galligan spotted an ad with an install button on the Twitter app for the iPad.

tweet installs 520x308 Twitter appears to be testing app store links and other customized links within promoted tweets

Update: CNBC’s Eli Langer also noticed customized links accompanying this tweet from Volvo, although we can’t find the tweet in question (which was also promoted) in the @volvocarsus timeline:

volvo 520x394 Twitter appears to be testing app store links and other customized links within promoted tweets

Twitter recently introduced app installs and deep-linking through its Cards feature, so advertisers can now promote tweets prompting users to install their apps.

Business Insider reported last month that Twitter was testing the new ad format. Twitter introduced native in-stream install ads through the MoPub Marketplace earlier this month, but this is the first time we’ve seen them in the official Twitter app. Rival Facebook’s app install ads have been a success for the company, driving “real revenue” according to CEO Mark Zuckerberg.

Twitter declined to comment when contacted by The Next Web.