.We have an ecommerce contact widget (chat, SMS, callback and email, with Whatsapp and Hangouts coming soon) that lets store visitors contact the owner and have a conversation through any of these channels. This drives conversion rates, since visitors can get their questions answered instantly without waiting for email to get turned around.
We provide a huge advantage over chat widgets, in that when a visitor starts a chat, he becomes a lead. The seller has his phone number or email. And the visitor who has a question and would normally leave the site to google it now can leave his number and get an answer through a callback or SMS.