This is actually a very good idea. But most users have a throw away email address for registrations and one for personal use. And for me for example, if i click a mailto link it will open the mail client with my personal email so I'll have to copy paste all that into my gmail throwaway email that may not even be opened. So I'll have to open the browser, click on........ But is indeed a good workflow alternative to consider for email verification.
Valid points. I hate mailto links in general, and can totally see the workflow getting messed up by not having your default mail client set to what you actually want.
However, I think most people know how to at least access their email (always logged in), so provided you could get them into their client, with a token, quickly, with a small number of clicks, might be interesting. Of course, it could be spam central.
