The Yahoo-branded application, available in early January, will let people search their PCs as well as the Web via Yahoo Search, but future iterations will include navigation for Yahoo's instant messenger archives, address book and free e-mail service.
Why should you use Yahoo! Desktop Search (X1) instead of other desktop search tools:
Relevance: Ability to pivot data by any dimension: recency, creator, recipient, type, etc.
Comprehensiveness: Ability to index 225+ data types, email attachments.
Freshness:V1.0 Beta: Scheduled in increments ,V1.0: near real time
Presentation:Rich native user-interface Search-as-you-type, previews, post-search actions.