Back in November, TechFlash reported on a new startup, Twilio, from Amazon Web Services veteran Jeff Lawson, that allows developers to build phone system applications in the cloud. Today Twilio took a big step forward, scoring funding from the Founders Fund and Mitch Kapor, and announcing a slew of customers.

Twilio didn't specify the amount of funding, but said it would use the money to expand its platform and its sales efforts. Current customers include Sony Music; Earth911, a recycling website; and Tumblr, a tumblelogging site (quick, mixed media blog posts). Twilio said the Heineken, Cheetos, Exxon/Mobil and Monsanto's Roundup brands are also "benefiting" from its technology.

Twilio lets developers quickly build advanced voice applications, such as automated calls or recordings, without having to pay for complex and expensive telephony software. The applicatons are hosted in the cloud and can be scaled up or down as needed. Twilio charges users on a pay-as-you-go basis, much like Amazon does with its web services business. Sony Music, for example, has been using Twilio to record artist messages to fans as part of album promotion, Lawson said.

Twilio investor Mitch Kapor has an interesting resume. He was founder of Lotus Development Corp and designer of Lotus 1-2-3. Kapor was also a founding chair of the Mozilla Foundation, co-founder of the Electronic Frontier Foundation, and a founding investor of RealNetworks, according to his web bio.

Twilio has offices in Seattle and San Francisco.