Online sales were up 17% in Q2, Mercent says

Overall e-retail sales grew 17% during the second quarter compared with the same quarter a year ago, according to Mercent Corp.’s eCommerce Performance Index. The index is based on same-seller sales of 120 Mercent clients.

Mercent, which facilitates retailer sales through online marketplaces like Amazon.com and eBay.com, as well as shopping portals like Google Product Search and comparison shopping engines, says e-retail performance remains strong, although growth slowed during the quarter compared with the Q2 2010 growth of 45% reflected in the index. Mercent CEO Eric Best  says growth rates as high as 45% are hard to sustain. He also says online sales channels, like Google, are continually refining their search algorithms and developing stricter policies about what data sellers and advertisers can share, which makes it harder to net sales growth.

Mercent clients that sell through Amazon’s marketplace program saw sales grow 35% during the second quarter, which Mercent says outpaces organic e-commerce growth. Amazon’s marketplace also led in sales volume for all channels tracked in the index.

Clients selling through all Google retail sales channels, including Product Search, Product Listing Ads and the Google Affiliate Network, grew 21%. Mercent says sales though eBay kept pace with overall e-commerce growth, but did not disclose a specific growth rate. E-retailer clients saw sales coming from top comparison shopping engines grow approximately 19% during the quarter. The shopping engines included in the index include Nextag, Shopzilla, Shopping.com, Pricegrabber.com and Amazon Product Ads.

Based on its analysis of current and historical data, Mercent says it expects the 2011 holiday shopping season to deliver solid double-digit percentage growth that may be slightly weaker than the gains posted last holiday season. Mercent says same-seller sales were up 25.5% during the fourth quarter last year, the quarter that includes most holiday sales.