As useless as walmart's website is, I doubt that HN could break it by simply visiting. As the other poster said, if it's broke, that's probably due to black Fri/holiday traffic.
Being on the front page of HN is worth about 20,000 hits a day in my experience. My $5/month VPS running every single page load through the incredibly slow BeautifulSoup parser handles it no problem. A link in the comments is probably an order of magnitude less traffic than that.