Denver, Colorado-based NewsGator, a firm which develops software for reading and monitoring RSS feeds used by blogs and others, said earlier this week that it has launched an add-on for Microsoft's popular Sharepoint portal software. NewsGator said that its product, NewsGator Social Sites, is an add-on to Microsoft Windows SharePoint Services 3.0. The add-on allows for delivering RSS feeds into SharePoint Server, and tracks if items have been read, filters messages by tags, and allows subscription to feeds. The new software also allows users to mark Sharepoint document items and list items are "read" to help users filter out old items. NewsGator's technology is used by companies to reading and managing news, blogs, and other RSS-based information streams. The firm is venture backed by Masthead Venture Partners and Mobius Venture Capital.