Layer2 offers Auto Tagger for SharePoint 2010.
– For the automatic reasoning of tags to be assigned to list items and documents.
– The reasoning engine analyzes a variety of inputs to decide which tag items to apply, including the contents of documents or files.
– For SharePoint 2010.
– Available immediately.

Atalasoft offers a universal document and file viewer for SharePoint.
– Means that users can preview documents and files within SharePoint, without opening the associated document or file.
– Works in document libraries, and search results.
– Supports synchronous scrolling, to compare two documents or files.
– The Pro edition adds annotation and markup capabilities, Web-based scanning, metadata searches, and more.
– Available immediately.

Adlib Software offer a PDF document transformation engine for SharePoint.
– Enables documents to be converted to PDF and stored in SharePoint, either on-demand or according to list/library item metadata.
– Multiple documents in SharePoint can be combined into a single PDF.
– See the Adlib Blog for more insight.
– Supports SharePoint 2007 and 2010.

Alan (from Socialtext) has a video on Socialtext and SharePoint integration.
– Enables Socialtext Signals (microblogging) to be added to SharePoint.
– SharePoint events can be shown in the Socialtext Activity Stream.
– Alan demonstrates Socialtext within SharePoint 2010.