Please see this link to help point you in the right direction if you're looking to remove the "powered by".
**FYI that this will likely void ANY and ALL support from StackIdeas by removing the "powered by" link if you're running the community version:
http://stackideas.com/forums/how-do-i-remove-footer-link
I believe that due to the type of open-source licensing that EasyBlog and these StackIdeas scripts fall under, once you've purchased the product you can modify the software as you see fit...which would include the ability to remove the footer should you desire (plz correct me if I'm wrong StackIdeas).
BUT remember the following is just an example and the location of the code may have changed by now, but it's usually easy to remove just a footer when you find the right line that displays the output code.
Reference info from the link I provided:
Ah, if you purchased the Pro edition, the link back is removed automatically but you can remove it by removing the codes in the file /components/com_easydiscuss/controllers/controller.php at line 240,
echo DISCUSS_POWERED_BY;