In most of the Windows operating systems, one of the Microsoft email application comes as the default email application, which opens up when you click on an email id in a webpage, which uses the mailto: HTML tag.
My rule is never to click on an mailto: link. Instead, I always copy the email id (or the mailto: hyperlink) to my mail compose window. This helps me to avoid sending to any wrong address given the hyperlink and also to prevent from opening Outlook or Windows Mail applications. This is good especially when you are not working at your own desktop.
Many folks use Gmail or Google Apps as their preferred email. When clicking on a mailto: link, it would great if the gmail compose window is opened in the browser, rather than Outlook or Windows Live Mail.
There are two easy options to set Gmail or Google Apps Email as your default mail client – use settings in Google Talk or Google Email Notifier.
If you use Google Talk and would keep it running always, just changing the options will take care of this mailto: links.
Go to Google Talk Settings => General tab and check the box Open Gmail when I click on email links. It is better if you keep the Start automatically when starting Windows option checked. This makes sure that, whenever you click on a mailto: link, Gmail compose window is open. This method works for Google Apps also. That is, if you are using Google Talk with the email at your domain powered by Google Apps, the same email account will be used for composing emails to the mailto: link.
If you wish not to use the Google Talk, try Gmail Notifier. The Google Notifier from Google works for the gmail.com domain only. Go to Options in Google Notifier by right clicking on the icon in system tray. Make sure that Use Gmail for internet mailto: links is checked.
If you are a Google Apps for domain user, use the Sohail’s Gmail Notifier for Google Apps. This notifier works with gmail.com as well as any domain hosted on Google Apps. In order to use it for multiple domains login can be changed at run time.
Go to Options in Sohail’s Google Notifier by right clicking on the icon in system tray. Go to tab Mailto/Proxy Settings and set Sohail’s Gmail Notifier as default mail client.