Richrelevance nabs $4.2 million for shopping-referral tech

If Amazon would have spun off its recommendation engine to Web publishers and retailers years ago, the company might have pre-empted the spate of new up-and-comers with similar technology.

But then again, if that were the case, the former chief of Amazon's data-mining and personalization group David Selinger wouldn't have seen a hole in the market and started Richrelevance. The San Francisco-based company, which makes software that delivers related product links to prospective shoppers, is in a hotly contested niche with start-ups Aggregate Knowledge and Loomia.

On Tuesday, Richrelevance was buoyed with a fresh investment of $4.2 million from investors including Greylock Partners and Tugboat Ventures. The funding announcement comes roughly a month after the upstart raised a first round of financing from Draper Fisher Jurvetson and Draper Richards.

Recommendation rival Loomia recently closed on $5 million in financing from Asset Management, among other investors. And Aggregate Knowledge has raised an estimated $25 million from Kleiner Perkins Caufield & Byers, among others.

As part of Richrelevance's funding deal, Tugboat Ventures' David Whorton and David Strohm of Greylock Partners will join the company's board. Ellen Siminoff, former Yahoo vice president and founder of Efficient Frontier, is also on the company's board.