Company quietly launches beta version of feature that's already offered by competitors Microsoft Corp. has quietly added video search to its Windows Live search engine.The new feature, which is in beta form, allows users to type in search terms and find video clips related to those terms. Users can test the new service .Results are displayed with a still photo of the video, and a brief description of the contents of the video. Microsoft joins Google Inc., Yahoo Inc. and America Online Inc., all of which already provide search engines for online videos. The software company continues to add services to its Windows Live services portfolio in an effort to bolster online ad revenue.Microsoft rebranded its MSN search engine under the Windows Live brand as part of its Web-based services push, first launched in November 2005. DatabasesSoftware Development