honestly, I don't think it will make one bit of difference, except on the off chance the hiring manager happens to be a Mensa member too. in the software world, what matters is results as well as the ability to work well in a team. What impresses most is the ability to demonstrate that you have achieved and are capable of continuing to achieve results. Best way to demonstrate this is:
- show that you can answer technical questions in the interview process, particularly when it comes to elegant coding skills
- talk about what you have achieved in the past when it comes to software/coding projects/etc
People who interview you will be impressed by your skills and knowledge, not your club memberships. Here in Silicon Valley I work with excellent programmers some of whom are basically college dropouts and such.
someone who knows you are Mensa, will know you're intelligent. But intelligence doesn't necessarily mean you are good at coding, work well with others, enjoy coding 10 hours a day, etc, which are the important factors that go into the hiring decision, at least for developer jobs.