Costco Wholesale was the most loved supermarket in the US in 2011. 89% of opinions on the grocery giant were positive last year.

Only Wholes Foods Market could rival Costco on social media. Over 90% of opinions on the organic specialist were positive in 2011 but Costco came out on top for the year thanks to the much greater volume of comments on the chain.

The secret of Costco’s success? Samples. By far the most common reason to praise Costco on social media was its samples. Consumers appreciated the free tid-bits as well as the chain’s pizza and chicken.

Supermarkets overall couldn’t muster much enthusiasm from social media users in 2011. Only 51% of opinions on US grocery stores were positive in 2011. Walmart must take much of the blame for supermarkets’ poor performance as the retail giant dominated conversations.

If you’d like more information on US supermarkets’ performance on social media in 2011. See Amplicate’s new report ‘Public Opinion on US Supermarkets on social media in 2011’, which tells you what consumers said about supermarkets on social media last year, when and where they said it and why.