Table 4.
Intercoder agreement for our labeled datasets (Krippendorff alpha).
| Category | WebMD | TwitterHealth | Google+Health |
| Share experiences | 0.349 | 0.446 | 0.109 |
| Ask for specific medical advice or information | 0.768 | 0.225 | 0.108 |
| Request or give psychological support | 0.219 | 0.090 | −0.007 |
| About family (not about self) | 0.736 | 0.322 | −0.010 |
| Share news | N/Aa | 0.083 | 0.083 |
| Jokes | N/A | 0.177 | 0.029 |
| Advertisement | N/A | 0.220 | 0.107 |
| Personal opinion | N/A | 0.103 | 0.038 |
| Educational material | N/A | 0.164 | 0.091 |
aN/A: not applicable.