Here's something I just noticed.

Search for [site:www.google.com/calendar/embed -inurl:mode -inurl:dates] on Google:

http://www.google.com/search?q=site:www.google.com/calendar/embed+-inurl:mode+-inurl:dates

(The -inurl:mode -inurl:dates just removed duplicates.)

Anything after the "src=" parameter is an email address. Sometimes it's URL encoded. Those spam bots but be loving that!

Admittedly, using an email address rather than a random string is easier to implement (for the user, at least) but it is really fair that just because someone wants to share their calendar, they must also expose their email address?

More spam == better spam filter ;)

This is a serious issue.

My yahoo account receives at spam e-mails per day . I am very careful and tag them as spam, but every day at least 4 new spam e-mail arrive,

I don't want to see this on gmail. It will be very sad thing!