I found some answers of mine chosen as most helpful and some of them has the word Auto written next to most helpful
what's the difference and what does it mean
Most Helpful Girl
If you don't choose a Most Helpful opinion within 30 days, the system will choose one for you based on engagement; votes, comments, length, time, Xper level, gender, among other criteria.
The opinion owner is NOT notified when the system chooses it, only if YOU choose it.
When you choose it, both you and the Most Helpful opinion owner will receive the MH Xper points. If the system chooses it, no one gets those Xper points.
For reference, this info can always be found in our FAQ ^_^