Yes! It's possible! :)
Gmail can be considered as the best site to send emails. It combines various features of chatting with it too. Yahoo, Hotmail, AOL are other mail sending sites.
Yahoo, gmail, and facebook
Yahoo is known where your friends send you emails and you send them emails back.
You can directly send mails from Google to Yahoo. The Gmail supports this feature of sending mails. It can send mails to Yahoo server as well.
You cannot send messages to Gmail without an account. However you need not to get a Gmail account only. You can also send it from yahoo mail like services.
You can send emails to anyone else with an email address ... google, yahoo or whatever
If you send a mail using Gmail, it will only be seen in the Gmail sent box. You can see it on a mobile in Blackberry too. However you cannot see the sent in Yahoo and Hotmail as they are different.
Gmail allows sending mails to other servers other than theirs. The mails can be sent with attachment to others like Yahoo mail. Hotmail is also a service to which it can easily send.
Yes, sending and receiving messages on Gmail is free.
Yes
With Yahoo! Mail, you can not only send plain text emails or messages containing attachments.
Emails can be of any type of gmail. You can send a professional mail or a personal mail. You can also attach various attachments with it.