SP1 is out, and there are some improvements and fixes relevant for the developer. This is a brief summary, with links to additional information.
- More flexible property extraction. FAST Search for SharePoint enables you to create your own property extractors. In this way you can extract names and concepts from the crawled content and add the normalized extracted values in new or existing managed properties. This is useful if you enable query refinement on the managed properties.
With SP1, there is no longer any restrictions on number of custom property extractors. Another improvement is that you can configure case insensitive property extractors. For most use cases this makes the configuration much simpler.
Note that you now use a separate configuration file for property extractors. If you already have created custom property extractors, you can easily migrate to the new configuration format if desired (but existing configuration will still be supported for backwards compatibility).
For more details, see updated documentation on MSDN: Creating a custom property extractor.
- Configurable title and date extraction for Word and PowerPoint documents. This is an alignment with the existing behavior in SharePoint Server search. After installing SP1, the title and date for these documents are retrieved from the content of the documents (if found), rather than the document metadata. Document metadata is often misleading, as users often writes new documents based on other documents or templates, and do not update the metadata. This is normally the desired behavior, unless your organization have policies and processes for keeping document metadata up to date. If you want the old behavior, you can configure this in optionalprocessing.xml. For more details, see updated documentation on MSDN: Configuring Optional Item Processing.
- Correct handling of refiner names with uppercase letters. In the RTM version you must specify refiner names in lowercase, even if the associated managed property contains uppercase letters (such as "Write"). This fix applies to the refinement panel web part configuration, query web service and query OM. There is also a similar fix for managed property names in scope filters.
- Using Keyword Syntax queries with non-default full-text index. This means you specify the full-text index as a property filter in the query. This will now return correct results.
See also the full list of improvements and fixes: Summary of FAST Search Server 2010 for SharePoint SP1 improvements and fixes.