Business loans may be hard to come by, but in the past three days, four emerging companies have revealed that they're receiving a total of $143 million in investment funding. Here's how Connectiva, Digg, MOD Systems, and OpTier plan to spend the money.

On Sept. 23, Connectiva Systems, which makes revenue and risk management software for telecom companies, disclosed that it has secured $17 million in funding from a group of investors that includes SAP Ventures. It plans to use the money for R&D, sales and marketing, and to scale its operations. Connectiva's software helps telecom companies stop “revenue leakage” through fraud management, credit risk analysis, and other analytics.

Connectiva (founded in 2000) has one foot in the United States and the other in India. Headquartered in New York, the company's development center is in Kolkata, India. Likewise, one of its investors, VC firm NEA-IndoUS Ventures, has offices in Bangalore and Santa Clara, Calif.

OpTier, which specializes in business transaction management software, disclosed on Sept. 23 that it has secured $47.5 million in fourth-round funding, plus a $15 million credit line. Morgan Stanley is among its new investors. The company says it will use the money to fuel growth -- both organic and through acquisition -- and to support sales and marketing.

OpTier (founded 2002) introduced its flagship product, CoreFirst, in 2005. The software prioritizes IT transactions based on business needs. Headquartered in New York, OpTier's R&D center is in Israel.

On Sept. 24, user-submitted news site Digg.com (founded 2004) announced a $28.7 million investment led by Highland Capital Partners. Digg CEO Jay Adelson, in a blog post, explained that the money will go toward infrastructure, international expansion, hiring, and site development, including personalization, an enhanced recommendation system, and more ways to discover and organize content.

On Sept. 25, MOD Systems (founded 2005) said it has negotiated a $35 million investment from Toshiba, NCR, and others. MOD's platform is a kiosk-like distribution system for movies, TV shows, music, and other content.

Toshiba and NCR aren't just investors, but partners. Under the agreement, users will be able to download content to Secure Digital cards, cell phones, and other mobile devices through kiosks managed by NCR in retail stores, airports, and restaurants. Toshiba will develop set-top boxes and SD cards for the system.

What does this all add up to? The four companies serve different niches, but they're high-potential niches -- risk management, transaction management, user-generated content, and mobile media, respectively.