Jerry Yang shares at least one thing in common with Marissa Mayer besides briefly holding the title of Yahoo CEO: Both Yang and Mayer are keeping a close eye on startups in the mobile space. But while Mayer is searching for mobile startups to acquire in order to bring engineering talent to Yahoo, Yang is looking for promising mobile startups to advise as part of his post-Yahoo life as a startup investor.
Yang most recently participated in a $1.2 million funding round for Polar, an iPhone app that helps users quickly poll the community about everything from what outfit to wear to whether actors attending the Oscars should shave or not. Polar's mobile-first design helped it boost engagement early on — more than 1.5 million votes were cast in just the first month after it launched in November — and attract big-name investors like Yang.

Yang and his reps declined to discuss his startup investments further, but interviews with several startups in his portfolio, former co-workers and other VCs shed some light on Yang's motivations and philosophy for investing.  The portrait that emerges is of a tech titan bruised by his final years at Yahoo and eager to work closely with smaller companies, many of which were launched by former Yahoos.

For startups, the incentive to work with Yang is fairly obvious: his name alone lends extra credibility to a new company, and Yang's connections and experience can prove invaluable for entrepreneurs seeking the right introductions and strategic moves. In Hykes' words: "It's hard to compress more startup experience in one person." But for Yang, the incentive to dive into the startup world more than 15 years after taking his own startup public is likely a bit more nuanced. Kedrosky, the VC, believes that Yang is taking the "trodden path to redemption" by becoming an investor and trying to stake out a post-Yahoo career.