Aruna Vaidyanathan: I read that the federated search allows one to just return results from any datasource but does not really "federate" or "merge" results from multiple datasource. With that kind of architecture, how can it be called Enterprise Search ?
From Nate Treloar:
Federated search is a technique for bringing into a search app results from a source that, for various reasons, cannot be indexed directly by the search platform. An example of such of a source would be content from the entire Web, which can only be searched through a Web search engine like Yahoo! or Bing. FAST Search for SharePoint 2010 has the ability to index and make searchable content from multiple enterprise sources so it's an enterprise search platform in the purest sense of the phrase. With the addition of federation, it is possible to include in the search experience these external sources. It is true that it is sometimes desirable to "merge" results from federated targets into a single result. This is possible with some customization around the federated search API in FAST Search for SarePoint 2010, but the usual method for displaying federated results is to place them in their own web part.
De-duping and actual integration of results is a challenge with federated search. As Nates says, many times it is better to retain the context of search results (having the repository search results show up as a separate web part). There may be value to showing results from a sales application separately from those coming from a marketing repository or categorizing them as such. The context is retained as additional metadata.
We have a past webinar that we did with AIIM on federated search. I will see if I can post the slides and recording.