Yes, the twitter pipe would work only with registered Twitter applications.
But if I get you cottectly "I want to publish my blog/News to that social site."
- this can be achieved. One way is to create a custom pipe for your local twitter-like service, but currently there's a bug to be fixed about implementing this functionality.
What I can recommend you is to create an RSS feed that is publishing events, which you create in Sitefinity, and feed it in your other site. You can take a look at ASP.NET RSS Toolkit
and Creating a Feed
resources, I believe they would be very helpful.
the Telerik team