The initial API release is focused only on publicly shared data. That means that social media client developers, such as TweetDeck and Seesmic, can’t yet use the API to let users access all content shared with them on the social network. However, the API could be used to aggregate public posts and it should work for piping public posts from Google Plus to other services like Facebook or Twitter. However, it’s read-only so it would not be possible to post to Google Plus from another social media service. It doesn’t look like it will be possible to search Google Plus for posts with specific keywords with the current API.
API access enables more uses of a service, such as analytics and “social listening” features that have made Twitter and Facebook boons to customer service. Once searching is enabled, the API could enable companies like Klout, Zendesk and Salesforce.com’s Radian6 to access the social conversations found in Google Plus. It could already be used to enable integrations like the one already built by Kapow Software that takes activity streams from Google Plus and pipes them into enterprise systems like Chatter.