Why does it keep saying I tweeter stuff when I don't have a twitter account?

[sick of it]

ever since I opened a yahoo email account- it started doing this on my updates... i don't even have a twitter account and I closed my facebook account and STILL it will say I twittered ( I copy and pasted the following example):
"(my name) tweeted- This made u
s chuckle, too RT @dannysullivan: The Things Facebook Causes, According To Google, Yahoo & Bing, http://selnd.com/bAgYGX"

WHAT IS UP WITH UPDATES LIKE THAT? I never tweeted any of this- there is tons of stuff like this from twitter on my profile updates- How did it happen and how can I make it stop?
this is on my profile page in the "updates"- I can't open anything- it's just a list of things that my contacts say. EXCEPT that I don't have a twitter account- or a facebook account... Why am I getting updates from my self- on an account that I don't have- saying things that I don't say?

[Lyn G]

It is called spam, treat them as you would any other spam. STOP opening them! Opening spam alerts the sender that your address is a valid one and they send you loads and loads more. You can not completely stop all spam, but you can help to put a big dent in it.
Check mark them and click on 'Spam,' this should stop those addresses from being delivered to your inbox.
Use your spam guard and block address.
Look for the 'Options' link at upper right corner of mail screen and click on it
Options /mail options
Click on 'spam' in the list on the left.
Make sure spam guard is on, by checking in the little box.
Then in 'Blocked Email Addresses,' enter the E-mail address you wish blocked, in the box after 'Add a blocked address' and click on the 'add' button, then click on save changes at top left of screen.
You will never get mail from that address again.
This should help you to control your spam.
Other tips:
Do not ever open E-mail from people you do not know; and unless you are absolutely sure who it is from then treat them as spam.
Never, ever give out your account information or other personal information to anyone.
If you are on a site and you absolutely have to sign up for something, check the entire page to make sure you uncheck any lines wanting to send you any other info, notices, catalogs, ads, and the like.
Added detail:
Yes, spammers change one item in their addresses a lot, so you might try blocking the entire domain, by putting in
*@ thedomainyouwanttoblock.com
for instance: *@seeyou.com
Or, if they change the domain, instead of the company name you can block the name by putting in Imatheft_inc@*
Hope this helps