The Unbounce blog has an interesting new article about Third-Party tools and conversion . The article suggests that the Google +1 button (please click mine!) can add up to 2 seconds to a page load.
That, combined with another bit of data – 1 second extra page load could decrease your conversion rate in 7% – means you might want to think hard before adding any external tool to your pages.
They also suggest a way to use A/B testing to figure out the cost/benefit of using any tool.
