Lot of people are searching this. Actually, when your blog grows up and you want to send e-mails for marketing or any other purpose, then you need to extrat e-mail address from wordpress comments.
This is a nice idea to do this.
1-just login to your capnel and click on phpmyadim
phpmy admin will look similar to this window
2-Now, select your database, in this example we will select _wdp and click on it. then the screen appear will same as below one.
From the list given in left sidebar, just select "wp_comments"
3-choose "comment_approved(Ascending)" from "Sort by key" drop-down box which will sort the comments that you have approved instead of spammy comments.
[caption id="attachment_357" align="aligncenter" width="525" caption="you can exctract email addresses from wordpress comments"][/caption]
4-Now scroll down and click on Export button
5-you can save this file as an Exel(.xls) file as well as csv file so that you can import all email address to yahoo,msn,gmail,etc...
Now you can import this file from yahoo,gmail or hotmail account.
Now start email marketing righ now. If you find this helpofull for you then leave a comment.