As part of the Salesforce1 announcement, Salesforce showcased a list of apps on AppExchange that are 'Salesforce1 ready'. This includes several popular apps such as Box, Concur etc. I want to know how does Salesforce certify an app as 'Salesforce1 compliant' - is this done as part of the AppExchange security/ tech review process? Are there any guidelines on how to ensure your app is 'Salesforce1 ready'?
Having been involved in one of those applications, i can say that there was no official list of things they provided, maybe their will be in due course, though the documentation does a pretty good job of describing the features to use.
As such having your package make use of one or more of the following Salesforce1 features is going to allow you to be qualified as such. Primarily including Publisher Action's being the obvious one. Once your ready speak to your Salesforce Partner contact about your listing.
From the Salesforce1 Developers Guide...
Publisher Actions. These help keep your users within the conversation or feed in Chatter terms, by allowing them to respond to questions and take actions without leaving the feed to go to another page or part of the UI, only to have to return back to the position in the feed to continue reading. Such actions, have been coined by Salesforce as 'micro moments', since they should in essence be a quick action, with minimal prompts to get the task done and return back to the conversation. You can define this via declarative and/or programming approaches and they are actually available in the Web browser UI as well. You can read more about these in the developer guide here.
Mobile Cards and Visualforce Pages. This feature allows you to embed Visualforce pages that have the 'Salesforce Mobile Enabled' tickbox ticked into the detail page layout of the records when viewed within the Salesforce1. Much like you can do already with standard Visualforce pages and the detail page view when viewed from your browser. They are called 'cards' since they render in the mobile device as regions you swipe from one to another. They can contain anything you can imagine and is supported on a mobile via HTML5! You can read more about them here.
Flexible Pages and Tabs. Are a new type of page, simalar to Visualforce, in that they are developed using an XML based markup language, they currently have limited components, to allow you to present List Views, Recently Used and X lists. These pages can be added to the side bar for access by the user in the Salesforce1 application. You can read more about them here.