Yahoo has announced the acquisition of mobile task manager Astrid, as it works to build its mobile app arsenal under Marissa Mayer. 

Available for Android, iOS, and web, Astrid is considered one of the go-to task managing apps out there. One of its pinnacle features is on iOS, where users can add to-do entries with their voice over Siri. There is also great syncing among platforms, reminders, collaboration with Google Calendars and the ability to share lists.

In a blog post from Astrid co-founder Jon Paris, it sounds like Astrid will soon shutdown, as we suspect its technology and team will be filed into the ranks at Yahoo. Over the next 90 days, Astrid will continue as normal, but will stop accepting new premium subscribers. Furthermore, Paris says Astrid will be in touch with users on how to download data. He didn't come right out and say it was shutting down, but it certainly seems that way.

According to the company's numbers, it's now serving 4 million users, since launching in 2008. Astrid raised $400,000 in venture capital from the likes of Google Ventures (how ironic, given who's buying it) and others. Neither Yahoo nor Astrid has disclosed the acquisition price.

Since Mayer became chief of Yahoo in 2012, the company has snapped up several others as it works to grow. One of the more notable acquisitions was Summly, a mobile app founded by a 17-year-old. It was acquired for a reported $30 million. Mayer has stated several times that mobile is one of the main focuses of Yahoo for the future.

Last month, Yahoo rolled out a redesigned Yahoo app for iOS that included Summly technology and a beautiful weather app with Yahoo branding all over. It's not clear how Astrid will fit into Yahoo's mobile shift, though we suspect Yahoo has something up its sleeve.