International Business Machines Corp. is creating a business unit for its Watson supercomputer and starting a $100 million venture-capital fund to spur more apps built on the technology, a bid to accelerate the promising system's slow transformation into a big business.

The venture fund is part of a more-than-$1 billioninvestment IBM will make into the new Watson unit, which IBM plans to grow to more than 2,000 people, from several hundred today, the company said. Many of the new hires will be salespeople and consultants to help clients devise ways to use Watson.

'We are now moving into more of a rapid expansion phase,' said Michael Rhodin, an IBM senior vice president who will lead the unit.

The announcement comes as IBM is having difficulty turning Watson into a salable line of software three years after the machine defeated two 'Jeopardy!' champions on TV. The Wall Street Journal in a page-one article Wednesday reported that Watson's revenue is far from the company's ambitious targets.

IBM Chief Executive Virginia 'Ginni' Rometty has said she hopes Watson will generate $10 billion in annualrevenue within 10 years, according to the transcript of an October 2013 conference call reviewed by the Journal. She set that target after the executive in charge of Watson projected it would bring in $1 billion of revenue a year by 2018. Watson had recorded total revenue of less than $100 million as of late October, according to the transcript.

The company won't disclosefinancial information for the Watson unit, which Mr. Rhodin said would remain part of IBM's business analytics software portfolio. IBM last year projected the analytics unit would grow to $20 billion in revenue by 2015, up from a previous $16 billion target.

IBM is looking to revive growth after six straight quarters of revenue declines. Company executives, led by Ms. Rometty, see Watson's smart software as a valuable tool to answer tough problems. The company is building versions of Watson that can comb through studies and patient records to determine the optimal treatment for a particular cancer, or examine a customer's portfolio and recommend an investment strategy.

But the software can take years to develop, and doesn't work with SoftLayer Technologies Inc., the cloud-computing provider IBM recently bought for $2 billion. Moreover, IBM has yet to figure out a business model for Watson. IBM may license the software or charge companies a fee to access a series of digital Watson 'advisers.' It is also exploring ways to share in a client's results, such as new revenue or cost savings.

'We've made incredible progress,' said Mr. Rhodin. 'There is lots more to do.'

As part of Thursday's announcement, IBM said it is rolling out two new digital Watson advisers: one helps companies draw insights from mountains of digital data, and the other creates graphical visualizations of data. The company said it would also launch a 'Digital Life' service online so consumers can experiment with Watson to, for example, build an app that suggests recipes based on a person's dietary restrictions.

Another effort, begun last fall, allows independent software developers to write Watson 'apps,' much like those for smartphones and tablets. IBM might take a cut of the developers' revenue, much as Apple Inc. does with its app store.

More than 750 people and businesses have contacted IBM about working with Watson, the company said. IBM is assessing the proposals. The venture fund could attract startups to the Watson ecosystem and help them build their businesses faster, said Mr. Rhodin.

Fluid Inc., a San Francisco e-commerce consultant and software developer, hopes to build an app using Watson that would let consumers ask questions on a retailer's website, as they would with a sales associate in a store. Fluid CEO Kent Deverell says the app could help people to more easily find the products they need and prompt more sales. But Fluid still needs to finish the app, and find retailers to use it.