I am going to teach only in 'Italki.com' in future. After finishing my existing classes, I will close my account in verbling, so please find me in 'Italki.com'.
Verbling has many positive qualities but it does not allow to connect with students through emails and share external links. Very recently, if any message to a student contains any link, they are blocking it. So, I guess, 'Verbling.com' is not for me. There are many online resources which I like to share with my students.
'Verbling' is very clear about this policy in their website. It took me for a while to understand the impact of it.