Google is ramping up its Checkout online payments service with a promotion campaign ahead of a rumoured imminent major development.

The PayPal-esque conduit for customer-merchant transactions launched last June after its rival inked an exclusive deal to facilitate Yahoo! customers’ payments.

But the search leader has now apparently started a front-page promotion for the service in the US which credits user accounts with $10 when they make a purchase.

Meanwhile, Google sources as well as Checkout sellers are reported to have said that “something major is on the way” from the service, with developments expected in the next few weeks.

Both Google and Microsoft earlier this week made a play of their merchant services to the National Retail Federation convention in New York City.