A simple Google search reveals a huge range of free Twitter viewers. It's tempting to throw one at a projector and call it a solution for social media. Closer inspection of these options exposes critical challenges for the digital signage (DOOH) implementer. Twitter allows applications and services to be built on top of their user-generated content by exposing a rich application programming interface (API). A multitude of content is available via this interface, but accessing it can be problematic. The most immediately obvious way to display Twitter messages, or "Tweets," on a DOOH screen is to create a Flash application using this API. Flash is the de facto standard platform for interactivity in DOOH and the Internet at large. Unfortunately, we are quickly running into the limitations imposed by the Flash security sandbox.1 For their own valid reasons, Twitter's cross-domain policy prohibits third-party Flash applications from accessing most of their API. Thus, DOOH implementers are forced to host a proxy. server to relay API requests on their behalf.2 This proxy host imposes a single congestion point on the application: users are limited to 150 requests per hour, per IP address. Even a small DOOH network will quickly reach this limit, filling screens with stale messages or worse, no messages at all. Any requests passing through this proxy will also experience additional network latency and are likely to experience outages and congestion at the hosting provider. With Twitter's blessing, it is possible to create special "whitelisted" user accounts. A whitelisted account is capable of making up to 20,000 requests per hour. This is not an SLA: you should still expect to see Twitter's famous solution...... middle of paper ...... solution which would be prohibitively expensive. It has already become clear that attention is the new currency. When a campaign reaches a critical level of traffic, the moderator's mission shifts from "is this message profane?" » to “does this message deserve public attention?” » This is a different type of problem that requires a different user interface. Several human agents. Social media is global, multilingual and subject to explosive growth. Any DOOH platform that uses it should enable large teams of moderators to be productive with a minimal learning curve. The issues presented here are not unique to Twitter. Brands and users are starting to expect seamless interaction across multiple channels and social networks. Facebook, Foursquare and Flickr all offer their own APIs. Each will add their own unique challenges to digital signage.