The question is what do you consider working?
Avnet a major technology distributor has been using Twitter to discuss virtualization and has successfully intertwined it as a communications medium that people follow. If we consider Twitter as another means to communicate to customers, and prospects then we should be able to start to track some value. Depending on the value of the content provided, you can help increase loyalty which in turn will generate sales.
Http://twitter.com/virtualpath Avent
http://twitter.com/virtualization Microsoft
So the real question may not be about the medium, but about how we use that medium.
Another challenge is that many of the social sites are heavily weighted to personal brands, as opposed to a commercial brand. That is a paradigm that needs to change in order to create true business value.
In my opinion, Twitter does breach the divide by providing that opportunity to expand beyond the personal, and create that commercial identity. As you see above with Avnet and Microsoft expanding their brands to Twitter. twitter.com/(companyname).
At the end of the day, Twitter is not a magical formula to success but an ingredient that may support success. For today, one of the best way’s to include it as an ingredient is to start building a commercial identity on Twitter. Then use it as another way to communicate to your constituents or subscribers, and value will come – if the content is good (but that is a conversation for another day.)