Chief Operating Officer Sheryl Sandberg launched a major charm offensive on Madison Avenue advertisers, touting revamped pages or mini-websites and timelines that marketers can use to promote brands and businesses to Facebook's 845 million members.

The new features let companies, as well as celebrities and brands, create self-contained mini-websites within Facebook using the Timeline format it introduced for users' profile pages earlier this year.

Facebook Pages will be available for smartphones starting later this year, executives said at an event attended by hundreds of advertising and marketing executives.

The world's No. 1 social network - which relied on advertising for 85 percent of its $3.7 billion in 2011 revenue - is ramping up efforts to attract the attention and budgets of large companies and advertisers ahead of its initial public offering.

It plans to raise $5 billion in an IPO expected to value the company at $75 billion to $100 billion, in Silicon Valley's largest-ever coming-out party.

Some investors worry about Facebook's over-reliance on advertising dollars.

Businesses can set up pages on Facebook for free, but the idea, executives said, is that companies whose pages attract a lot of customers might be interested in advertising on the service as well.

Macy's Inc, Coca-Cola Co and Wal-Mart Stores Inc were among the first to roll out new versions of their Facebook pages that gave them more leeway to design splashy, media-rich pages.

A new, chronological timeline on the right side of the page lets businesses create customized pages that incorporate images of memorabilia and milestones in a company's history.

(Editing by Edwin Chan and Richard Chang)

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