Google ( GOOG) is putting even more of its weight into promoting its Checkout service. The search giant kicked off a plan earlier this month to offer $10 discounts for first-time users of Checkout, which lets Web surfers make purchases on the Internet in a few easy clicks. And earlier this week, Google began promoting its new offer by plugging it in what may be the most premium territory on the Internet: An ad for Checkout is now posted on Google's home page, directly under the search box. Search results for some retail items also display a link that allows users to rerun the search incorporating only results for vendors under the Checkout umbrella. The $10 discount will be available to new users until Feb. 15, and follows on the heels of discount offers up to $20 during the 2006 holiday season . In November, Google also announced that it would extend its offer to waive processing fees for merchants through 2007. Google's ramped-up efforts will have implications for other major Internet players, most notably eBay ( EBAY), which owns PayPal, a fast-growing rival payment service that currently leads the market. For now, PayPal has yet to feel the heat from Checkout, despite many predictions of PayPal's demise when Google launched its own service last June. PayPal's adoption rate (the percentage of respondents who said they used the service) of 42% is seven times greater than the 6% for Google Checkout, according to a report released Wednesday by JPMorgan.