Darren Vengroff, the former Amazon.com engineer who resigned from Seattle startup Pelago earlier this year, has re-emerged in a new role at San Francisco startup richrelevance.

Vengroff, who will serve as chief scientist, said he plans to open a new Seattle office for the company with a handful of engineers.

Backed with more than $9 million from Draper Fisher Jurvetson, Greylock Partners, Tugboat Ventures and others, richrelevance provides personalized recommendation services to e-commerce sites.

That's a technology that Amazon.com -- where Vengroff worked from 2004 to 2006 -- is well known for with its product recommendation suggestions.

"The richrelevance team is an amazingly talented group of individuals that I cannot wait to join," said Vengroff, who co-founded the mobile social networking startup Pelago. "They have quickly established themselves as a market leader in both technology and customer service, delivering significant lift to their customers in a very short time."

Richrelevance is led by David Selinger, who previously worked with Vengroff at Amazon.com. Selinger, who led Amazon's Data Mining and Personalization team, also co-founded Seattle online real estate startup Redfin.

More on richrelevance's business from VentureBeat, which points out competitors such as Aggregate Knowledge and Wunderloop. The personalized recommendations arena was also an area that Seattle-based CleverSet was targeting before it was sold to ATG earlier this year for $10 million.