From small to medium-size merchants, that is how Twitter Inc. will begin to market its ads to merchants, casting a broader net for advertising revenue.

More than 3,000 mostly big companies which includes Wendy's Co., Volkswagen AG and Southwest Airlines Co., have paid to have their "tweets," posted prominently to people surfing Twitter.com, since Twitter started selling ads about two years ago.

The ad-expansion plan comes as Twitter works to live up to a valuation despite a heavy sum of $8.4 billion, based on recent private investments,

Twitter remains behind Internet companies such as Facebook Inc. and LinkedIn Corp. in creating revenue.

Debra Aho Williamson, principal analyst with eMarketer said “Until we see more of a natural state of things where Twitter isn't so actively involved, it's hard to tell how successful Twitter advertising is going to be.”

Twitter needs to upsurge its ranks of users to better please companies such as Bonobos Inc. in order to have its ad expansion succeed.

The company's vice president of marketing, Richard Mumby said Bonobos requested permission to start buying Twitter ads last year, also including to pitch a new line of suits and a holiday sale.

"Twitter has good promise," Mr. Mumby said. "The next phase in our relationship with them is how to crack that nut on how to be a big volume for new customers."