From Chip-In (worded same as on their main webpage when I verified this):
Thanks For All The ChipIns
February 4, 2013
InMobi will continue to own and hold on to the ChipIn brand, domain, and technology.
As of the date of this notice it will no longer be possible to create new accounts or ChipIns. Those with existing accounts will still be able to log in, copy and export data, manage ChipIns, update ChipIn pages, and accept contributions until the End Date. Chipin.com was started in 2005 as an easy way for individuals to raise money collectively and was one of the pioneers in this field. In six years Chipin.com helped thousands of users raise millions from contributors for wide-ranging purposes, including heart surgeries, pet adoptions, college graduation, disaster funds and much more.
Thank you for being part of the ChipIn community! It is gratifying to know that it has made a positive difference for many.
My heart sank when I read it. Crap.
I guess it was too effective.