Information such as auction bid updates, stock quotes, travel changes and bank transaction notifications will be sent out based on the customer's control and consent.
As part of the preview, eBay, MSN Carpoint and CNBC on MSN Money have deployed .Net Alerts in the US. More than 20 companies - including NASDAQ and Adopt - will begin offering the service to US users in the near future.
Christopher Payne, vice-president of .Net My Services at Microsoft, said: "In addition to providing convenience for consumers, .Net Alerts also will jump-start new ways for businesses to serve existing customers and attract new ones."
John Delta, vice president and general manager of NASDAQ.com, added: "Microsoft's .Net Alerts is a great Web service for investors, enabling them to track movement in the stocks that they are most interested in."