
The name of the link can be changed by adding one line to the custom HTML settings in the Confluence Adminstration.
Steps
Go to Confluence Administration → Look & Feel → Custom HTML
Click Edit and add following text to the section At end of the BODY:
<script>AJS.$('#lively-blog-all-link span').html('NEW_LINK_NAME')</script>
CODE

Replace 'NEW_LINK_NAME'
with the text you want to be displayed.
Save the settings