I think the problem may have started about the time we installed the guest map plugin. We have since disabled it.
Shortly after that installation we noticed that the Google Analytics code was not registering stats. WE tried moving it in the footer.php in the admin to see it that would help per a suggestion we found in a forum, but then the footer code wouldn't completely print to the browser. If I removed some characters in footer.php, I'd see more of what was in the admin footer.php actually printing to the page in the browser in the front end - but not everything. It was if there was a restriction on how many characters could be in the footer. I finally removed everything I could in the footer to be sure the .js was printing entirely, and that the whole page down to the </body></html> tags was there. If I tried to add more characters, it would truncate again. So I left it as is and assumed everything was working again. Then we discovered that people couldn't comment and tied this event into the time we installed the map plugin. We tried replacing footer.php with the default code, but still no luck. Now we don't know what to do. People still can't comment in the blog - when they try they see a blank page after submitting.