GiftRocket is a new web-based app that connects with PayPal to wire money for any business listed in Yelp to anyone with an email address and a smart phone. Say that you have a pal in San Francisco who put you up over the weekend. You want to thank him with a gift certificate for his favorite restaurant. Send him the certificate from the GiftRocket site and pay for it with a credit card or via PayPal. (GiftRocket charges 5% extra for credit card processing fees.) When your friend arrives at the restaurant (which will be confirmed by the GPS on his cell phone), he can redeem the gift certificate. Well, “redeem.” What happens is that your money flows into his PayPal account. From there, he can spend it as he will.