I realize this is an old thread and I apologize if I post in the wrong place. However, I am posting for the new version 1.6.1.6 of Prestashop on how I changed the text and link of the copyright notice. Thanks to everyone for sharing on the internet. After much reading and editing it turned out to be a combination of 3 things, not all found in 1 place.
Step 1)
Login to your BackOffice and navigate to Localization ->Translations.
In the drop down box labeled "Type of translation" choose Installed modules translations.
In the second drop down box labeled "Select your theme" choose your theme.
In the third drop down box labeled "Select your language" choose your language.
Click Modify in the bottom right corner.
In the list of modules you want to find blockcms
Edit the last box labeled ->"[1] %3$s %2$s - Ecommerce software by %1$s [/1]"
I changed mine to look like this-> [1] %3$s %2$s - My Store | Powered by My Hosting Company [/1]
Click save.
You can test this by going to Front Office/ Home page and refresh. The text should have changed. If you click it, the pesky link goes to Prestashop.com.
Step 2)
As Minca, eye-wonder and many others have said, you will need to edit the .tpl file. The file you want to edit is themes -> your-theme -> modules -> bockcms -> blockcms.tpl. The code in this version is different than most examples I have seen.
{l s='[1] %3$s %2$s - Ecommerce software by %1$s [/1]' mod='blockcms' sprintf=['PrestaShop™', 'Y'|date, '©'] tags=['<a class="_blank" href="http://www.prestashop.com">'] nocache}
All you need to change is the www.prestashop.com part to the link you want.
Example:
{l s='[1] %3$s %2$s - Ecommerce software by %1$s [/1]' mod='blockcms' sprintf=['PrestaShop™', 'Y'|date, '©'] tags=['<a class="_blank" href="http://www.my-store">'] nocache}
It seems that the rest of the text is grabbed from the text we changed in Step 1. Wait a minute! you say. I refresh my store and that pesky thing still goes to Prestashop.com! ...Proceed to step 3.
Step 3)
Not sure why this step is left out. Maybe in previous versions it was not needed or it is assumed (& we all know what that does). Anyway, here it is.
Login to your BackOffice. Navigate to Advanced Parameters ->Performance. Click the radio button labeled "Force compilation". Next to the label "Cache" click No. Click Save.
Wait for this page to reload. Then go to your Stores home page and refresh. The copyright link should be changed to the link you want.
Hope this helps someone save a little time.