I would also go as far as to say, if you aren't going to use these tools effectively, it might be better not to use them at all. There is possibly nothing worse than an inactive Twitter account or one that is used solely to broadcast one-way information. What's the point? Ask yourself, why are you using? Is it just because you feel you have to (well all the libraries are doing it now so....) or because you actually believe it can deliver value to your users and ultimately improve and enhance service delivery?
So what can you use these tools for and how can you 'justify' their usage to management? I am speaking mainly in the context of Twitter as it is the tool I believe is most important right now. But what should you tweet? Twitter is a great opportunity to promote your events and services to a captive audience. If people are following you on Twitter it means they are already tuned-in to some extent at any rate. Actively seek out those who may be interested in your service and follow them (not just users, but potential collaborators, competitors and so on). This is how you can build your network.
Twitter can also be a really valuable customer service tool. I think libraries should encourage its use in this way, as many commercial companies already do. Many users may tweet about problems or other feedback, rather than sending more formal complaints. However, this kind of informal feedback can be so valuable in informing and improving service delivery and enhancing your users' experience. Twitter can also help to build your reputation and virtual presence, show your followers that you understand and embrace new technologies, engage your users and strengthen relationships
You should always be thinking about your social media strategy and how you are using these tools in terms of your overall service. Some strategies to keep in mind include:
Innovation - be the first to do something, experiment, use Twitter as a testing ground for new ideas and services, investigate the potential for new services like virtual reference, collaborate with other departments by promoting their research through Twitter.
Streamlining and Integration - libraries have so many access points, services and resources today. Just like with discovery services, tools are generally more successful if they are integrated with overall service delivery. Don't think in isolation; your Twitter account should not be seen as something standalone. You should be displaying your tweet feed on your website to increase its visibility to your users. Focus on one tool if you have to and do it well. Always think of the user experience!
Be Proactive - share information that is of real value to your users by anticipating their needs. This will keep them interested. Initiate conversations; don't expect them to come to you. Show faculty the value of concepts like altmetrics before they start asking you about them.
There are obvious things you can tweet about: library events; new titles and acquisitions (why don't libraries do this more?); solicit recommendations/requests from followers; links to useful external and internal resources; obtain feedback (and don't censor negative comments, address them!). You always need to think of social media and networking tools in terms of building relationships with your users; if you forget this, it won't work.