Most of us use Gmail, but there's a small minority still clinging to hotmail or Ymail, because that's what their ancestors used when they were chasing wild goats. For all, here's how to get your browser to use you email service whenever you click an email address.
For those of you who've switched to using web-based mail, it might not be intuitive how to use links with "mailto:" URLs. You'll have to change the handling of mailto-links, to pass the address to a webmail service, instead of a mail application on your computer. You can see below a screen capture from my Opera 10.10 Portable (LK) Preferences:
In Tools > Preferences > Advanced > Programs, select 'mailto' and press 'Edit'. Enter 'opera' in the 'other application' field. Then use the addresses below to put in the 'Parameter' field:
Note: in some browsers, such as Opera 9.2, you put both together in the single field, as in 'opera "http://etc"' (without the single quotes).
Opera Web Mail
Hope this helps! Also, you are hopefully familiar with what a browser is, unlike the following people..