The problem you specify is that not everyone has an email program set up on their computer!
If you do a lot of gmail, yahoo, live or other online type emailing, your computer does not have a "default mail client" installed.
You can assign a program for your mail client in the browser TOOLS OPTIONS area.
If you have assigned a default mail client and actively use it, then your links open fine and you can send emails to that link.
If you have Outlook Express or Live Mail or Outlook, etc installed but are not actively using it, preferring to use online email clients, then your online link will cause your computer to try to open the link with what ever program it knows you have installed AND try to get you to set up your server info. (This fails, email is not sent, opportunity lost)
A FORM online will not have this reaction. Everyone can Fill & Send no matter what they use to read emails.
Lots of free forms that are a better option!
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Might I suggest you use an obfiscator to build your MAILTO links?
I strongly recommend using FORMS instead of mailto links to stop spammers from getting your addresses.
But if you really want to use mailto links, I suggest you Check out this free tool:
http://www.seowebsitepromotion.com/obfuscate_email.aspI have used it as MIXED setting with excellent results.
Fill in the blanks like this:
email:
blahblah@yoursite.com Link: John Smith
Title: Email from YourSite.com
Rollover: Click to EMAIL John
Click MIXED and OBFUSCATE to get a piece of code that is a bit garbled. (Some spammers can read this some can not. But if you use a standard MAILTO every spammer can read it!)
Place the code into an INSERT HTML box in CSB to get a nice email link that is a BIT safer than plain mailto link.
This is NOT as safe as using a form.