With the assistance of Ghostery, we’ve put together some data showing that social plug-in adoption among IR500 websites lags far behind adoption among all top sites. While 50% of all sites have a Facebook plug-in and 42.5% have a Twitter plug-in, it turns out that only 31% of the IR500 have any social plug-in at all (see our infographic after the jump).

This despite evidence that shoppers are becoming increasingly social, with 58% of online consumers having “followed” a retailer through Facebook, Twitter or a retailer’s blog.

While e-commerce sites generally feature less shareable content than publishers, we have to wonder if online retailers, whose conversions are so vulnerable to page-load time, are especially wary of the extra load time accompanied with installing social plugins. If these e-commerce sites are missing out on a valuable opportunity due to concerns about extra load time, they might want to talk with TagMan about our Smart Tag Loading functionality built into our latest release.