Why do my link popularity does not have the same result on some link popularity checker sites?

Because they calculate it differently. I wouldn't put any value on these contrived values, because they are next to useless. And as you've found, inconsistent.

ok thanks...so how about you? where do you go to check your link popularity?

I don't, as I see it as a waste of time. What good is being 'popular' if you don't get any visitors, or if you don't get any conversions (whatever conversions means to you)?

I would check whether my site was meeting its objectives (objectives I set), not whether it met some arbitrary criteria contrived by some tool pusher