I think AJAX stole the spotlight with MOSS SP1.. The feature I'm most excited with is External BLOB Storage Provider (EBS). "A large proportion of data files are represented as unstructured binary files—that is, binary large object (BLOB) data
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Read the complete post at http://blogs.microsoft.co.il/blogs/itaysk/archive/2008/01/22/external-blob-storage-provider-ebs.aspx