Yahoo unveiled a series of upgrades on Monday to its email, instant messaging and Internet search pages, as part of the company's plan to revive its online advertising business by making its core Web properties more appealing to users.

Popular Yahoo products such as Mail and Messenger will soon grow more social, allowing users to update their status, share photos with friends, and initiate video calls.

In addition, Yahoo Search is about to get a new results page that can connect searchers directly to the Web content they seek without leaving the results page.

Our user base grows when things are simpler and more delightful, said Elisa Steele, executive vice president and chief marketing officer at Yahoo.

Yahoo says it seeks to attract more people who are not already familiar with Yahoo's content and to entice those who already use products like Yahoo Mail to spend more time on the site. Through this, they seek to increase the amount of views its advertisers gets.

Yahoo also said it was working to develop a new search page design that will deliver contextual results that are more relevant to users' queries. Yahoo will then in turn offer a web of objects instead just a list of Web pages, like Google does.

For example, a query for how to make an omelet will return organic search results and sponsored results, as well as a column containing links to sites that specifically provide information on how to prepare sushi dishes. This could include how to videos from YouTube, which the user can view from within Yahoo's search results page.

The new Yahoo Messenger makes the Insider page that pops up when the application is launched look more like a home page. The Messenger app itself includes live video and voice, and users can drag-and-drop photos for instant-sharing. It will also allow them to see their friends' status updates.

Meanwhile, Yahoo Mail has also changed by increasing its maximum file attachment size, from 10 MB to 25 MB, and a redesigned Web mail site for mobile phones, launching today on the iPhone.