avoid spam: use altered email ids in threads/posts.
Avoid openly posting email addresses unless necessary.
[Email addresses provided here while registration are
secure and not shared]
When you use email ids, let it be yours or others,
modify it to username[at]domain.com
This is to avoid worms and bots roaming over the internet
taking over the email ids and using it for spamming, phishing,
email spoofing or spreading viruses and worms.
eg. if you want to give an email id like firstname.lastname@example.org
give it like myname[at]yahoo.com.
Or you could give your e-mail address as email@example.com
using "0" (zero) instead of "o." A person can interpret your address,
but the automated programs that spammers use cannot.
You can also use other formats like using an image for email id.
phishing : The luring of an internet user to reveal personal details (like
passwords and credit card information) on a fake web page or email form
pretending to come from a legitimate company (like their bank)
spoofing : emails which pretend to come from a legitimate user but
originates from fake users, spreading viruses, worms etc. Virus mails
you receive from your friends fall into this category usually. They are
not send by your friend but viruses which gathered both your friend's
and your email ids from an email or website.