The buttons to mark responses are currently the following:
I suggest to make the following change:
CORRECT ANSWER change to This solved my question
MARK AS HELPFUL change to This helped me
It should help to steer the focus away from a political or objective correct or helpful answer to which resposne was actually useful. People may occasionally be reluctant to decide. The difference may look trivial at first, but there is a psychological difference.
Using a more subjective style should increase the chances that people will decide to mark answers.
This is actually not just my humble opinion or imagination, but other communities have obviously adopted such a style, for example, the Apple discussion forum. Apple uses the same platform, albeit a previous version. Since OTN apparently uses a custom solution to have helpful answers, such a change could perhaps be implemented. Below is a screenshot showing an example: