A new report from SEO firm BrightEdge reveals that having a Twitter share button, like the one on the right, on your website can help drive up to 7x more exposure via social media.

And while the numbers back up the importance of giving your visitors an easy, one-click way to share your content on Twitter, many of the top websites aren’t listening. Less than half of the top 10,000 websites actually use any type of Twitter share button on their pages.

The “Tweet” and “Follow” buttons are free tools, and can be added to any web page with minimal knowledge of web programming. It appears as though it’s not the technical side of things that’s holding websites back from embracing Twitter.

There is clearly a missed opportunity for those sites choosing not to add social plugins like the Tweet Button to their pages. Visitors who see a button will share that content on Twitter, not only getting it in front of their immediate audience, but also possibly their extended network through retweets and virality.

While only 42.5 percent of the top 10,000 websites included a Tweet Button, not many more chose to adopt Facebook instead: only 50.3 percent have some type of Facebook plugin visible on their site. And, perhaps surprisingly, Google+ has beat out LinkedIn, with 8.1 sites choosing to display a Google+ button and only 4 percent showing a LinkedIn plugin.

BrightEdge examined four million randomly sampled tweets to discover just how effective the Tweet Button was at driving traffic.

Hat tip: AllThingsD