Twitter is heading toward an initial public offering, but its board of directors could prove to be a problem. Namely, there are no women. Each of Twitter's seven directors are men.  

Whether Twitter wants more diversity is unclear. But as anticipation for its IPO builds, Twitter risks coming under fire for being a boy's club--the way Facebook did before it hired chief operating officer Sheryl Sandberg. 

"You can't be disruptive if you exclude women," says Peggy Wallace, managing partner at Goldenseeds, a New York-based venture capital firm. Plus, Twitter's users are predominantly women--and young, tech savvy women at that, according to Pew Research Center's latest survey of social networking habits. Twitter needs the fairer sex on its side if it hopes to continue to grow and meet shareholder demands.

With the help of experts, we've compiled a list of five women that Twitter--and any tech start-up--would be lucky to have on its board:

Lorrie M. Norrington

As president of eBay International, Norrington oversaw everything from planning to product development for its network of sites in Europe and Asia. When she was promoted to head the North American business unit of eBay Marketplaces, she was a quick study on online shopping and why customers loved it. Such knowledge would be useful to Twitter as it looks to create new revenue streams by catering to local businesses and global brands. 

Mindy Grossman

Since becoming chairman of HSN in 2006, Grossman has transformed the home shopping network into a lifestyle powerhouse with sales of $3 billion a year. A 34-year veteran of the retail and apparel industries, Grossman has also held senior positions at Nike, Tommy Hilfiger, and the Polo Jeans Company. That experience would be an asset to Twitter as it markets services to e-commerce sites and retailers. Although Grossman serves on the board of the National Retail Federation and a few other organizations, she may be willing to carve out time to help Twitter go public--something HSN accomplished in 2008. 

Bonnie Hammer 

The chairman of NBCUniversal, Hammer knows media. "She's a real powerhouse," says Janice Ellig, co-chief executive officer of Chadick Ellig, an executive hiring firm in New York. Under Hammer's watch, Syfy became a global brand, USA created a stable of top-rated and award-winning shows, and E! Entertainment transformed into a go-to destination for fans of pop culture. Hammer's media savvy and connections would prove useful as Twitter tackles social TV and tries to make start-up acquisitions like Trendrr, Vine, and MoPub pay off. 

Sally Krawcheck

Known as the former First Lady of Wall Street, Krawcheck held executive roles at Bank of America and Citigroup. "She's not a digital person," says Ellig, "but sometimes you don't want everybody to be the same so they can raise different issues." Krawcheck is no stranger to regulatory reform and investor protections. She also knows her way around a balance sheet and could certainly help Twitter appeal to female users. She recently acquired 85 Broads, a global women's network.

Marissa Mayer

Who better to advise Twitter than the Silicon Valley icon herself? Yahoo's CEO has proven herself a competent corporate tech strategist. Plus, as an early employee of Google, developing search is in Mayer's blood. That could prove very useful to Twitter, which presumably hopes to make money by placing relevant ads in users' searches. Though she fits the bill, Ellig worries Mayer may be "overboarded." Mayer already holds board seats at Walmart, Jawbone, Cooper-Hewitt, and the New York City Ballet, among several others.