Would custom social sharing buttons work better than the bulky addthis widget on a highly trafficked website (100mil pageviews/day)?
Using addthis on a high traffic website
social media;addthis;sharing
Yes, mainly because most large social network's code is delivered from a powerful CDN. I would advise loading the scripts at the foot of your page as this will mitigate the script's effect on your overall page load time and user experience.