Groupon has a roaring head start in the deals of the day category for groups, with more than a million users. We’ll hear all about Groupon from CEO Andrew Mason at next week’s Marketplaces conference in San Diego, where he is keynoting. But there are now countless imitators adding their own deals.

New York-based 8Coupons.com, which aggregates coupons from content partners such as Valpak, Money Mailer and RedPlum’s SuperCoups, has now put them all together in one spot (great idea). 8Coupons launched the top 10 U.S. cities last month, and now has 55 different Group Buying “Deals of the Day” Web sites in 100 cities. Based on what we are hearing around the industry, many more sites are likely to enter the space soon.

Groupon has a roaring head start in the deals of the day category for groups, with more than a million users. We’ll hear all about Groupon from CEO Andrew Mason at next week’s Marketplaces conference in San Diego, where he is keynoting. But there are now countless imitators adding their own deals.

New York-based 8Coupons.com, which aggregates coupons from content partners such as Valpak, Money Mailer and RedPlum’s SuperCoups, has now put them all together in one spot (great idea). 8Coupons launched the top 10 U.S. cities last month, and now has 55 different Group Buying “Deals of the Day” Web sites in 100 cities. Based on what we are hearing around the industry, many more sites are likely to enter the space soon.