The lesson learned once again is that everyone is prone to failures (Google, Facebook, Twitter, etc) some will experience downtime and others slow performance. As a site owner (or developer) you need to be prepared for these kinds of failures, you need to build your site knowing that failure will happen. Some things to consider:
- Wait for your content to load before executing these 3rd party calls.
- Have a mechanism of detecting and removing very quickly the offending tag(s).
- Test your site for single points of failures.
- Demand accountability from third party providers, and require SLAs.