Google Allo will keep your messages on its servers until you delete them
Google is backtracking a bit from what they’ve announced at Google I/O and sharing how they plan to store messages on its new Allo app. If you’re not using Incognito Mode in the app, the messages you send there will be stored “transiently.” What this means is your chat history will remain on your device and Google’s servers until you physically delete them. According to Google, they made the change to improve the smart reply feature of the app. Of course, the messages will remain encrypted. But if you don’t want to have to delete the messages yourself (the one you’re messaging has to delete them, too, to completely remove the data), you can choose to use Incognito Mode within the app.
Source: Engadget + The Verge | Download: Google Play Store + Apple App Store