Luckily, many websites and is still common to find a contact form that we avoid using our own tools to send our communication to those responsible for such websites. Still, there are still sites that use the mailto: protocol that will open the mail system that we default in our system. And if our system does not give us many configuration options for webmail, nothing happens in the event that Google Chrome is our main web browser.
Mailto: is an extension for Google Chrome that will allow us to choose the webmail that we use in our communications. We can select one or more options, being in the first case when we open a tab with the web interface of the composition of elected webmail messages. In the second case we will choose in each moment we want to use webmail. We may also use other default webmail that are not supported.
In this way, and only in those cases where we have a contact form and if an email address in a mailto: link, we can use webmail you want by default for us.
More Info: CNet