Why would I want to use corlive.com instead of my e-mail ?
Because e-mail is simply unreliable. Please see about Corlive.com and then the spam case study
Does a sender need to be registered with Corlive.com to send me a message?
No, anonymous users can send messages as well.
Is this service completely free ? If so, then how can I start using it?
Yes, of course it is free. Both for personal and business use. As a start - register to get a free account at Corlive.com
How can Corlive.com be spam-free when there is no CAPTCHA on contact pages?
CAPTCHA is automatically activated for users who send more messages than on average.
Is corlive.com/johnsmith the same as corlive.com/JohnSmith? Are logins/contact pages case-sensitive?
Logins aren't case-sensitive. You can use johnsmith as well as JohnSmith, the same with contact page url.
When I publish my corlive.com contact page, can I specify the subject?
Yes, for example: http://corlive.com/johnsmith?subject=your subject goes here. The same with a message, example: http://corlive.com/johnsmith?message=some message. See also: publishing contact url.
Are there any limits in Corlive.com?
Yes, you have about 100 MB of storage space. To increase this limit you can simply invite your friends to Corlive.com.
What's "Read status"?
It tells you whether the recipient has read the message. It only works when:
a. the recipient is a registered Corlive.com user
b. the recipient has marked the "public read status" checkbox in preferences
If the recipient will read the message but then will mark it as "unread" you will see it as "unread"