Mr. Giles. (Bloomberg)

Roboinvest, which lets ordinary folks follow each others' trades in real-time, booted up at the end of January with a partnership with amateur trading clearinghouse E*TRADE. The startup has processed $2.5 million in trades and grown to 1,300 users since then, founder Michael Giles told Betabeat, with only some seed money and a full-time team of two.

The trick to Roboinvest is "one-click copy trading," the feature that launched just over two weeks ago and got the attention of Bloomberg's Businessweek. Broadcast your trades in real-time on Roboinvest, and your followers have 30 minutes to decide if they want to copy your move. "Most people know somebody who trades, and they always want to know what they're doing," he said. "It's trading for the rest of us. Anybody with a trading account can use Roboinvest."

People chat about stock picks on Twitter and the niche site StockTwits, where anyone can claim to beat the Street. Because it's directly connected to a trader's E*TRADE or TradeKing account, Roboinvest only broadcasts "pure signal," Mr. Giles said, because every broadcast is an actual trade. "It's like looking over the shoulder of what another trader is doing," he said. "It's a bit of that voyeurism aspect to it."

Eventually, Roboinvest will automate the trades the way other startups like Covestor have, Mr. Giles said. Covestor, another New York startup, peddles what it calls "mirror trading." Covestor curates a group of model managers and tracks their earnings so ordinary traders can comparison shop. Follow a model manager, and your money automatically follow theirs. The model managers and Covestor then take a cut.

"We want to get to the point where we can add a lot more automation into the service," Mr. Giles said. The delay is in part due to financial regulations that affect automated trading, he said. "We're going to keep it self-directed and learn from that and optimize it, then take it to the next level after we've made the one-click trading super solid."

Within two weeks, Roboinvest will begin supporting the e-broker TradeKing, adding another 300,000 potential customers on top of the 2.8 million on E*TRADE.

Roboinvest plants to release one-click trading on its mobile app soon, rehaul the website, and integrate with more smaller online brokers.

Mr. Giles is from Melbourne, Australia. He studied abroad in upstate New York and traded stocks while in school. His friends were always asking him for advice, which led to the idea for Roboinvest. Ultimately, he believes Roboinvest's appeal will be its community. "Our tagline is 'invest together,'" he said.