What's the meaning of mark in this paragraph?

[Maggie]

Americans are marking the election of Barack Obama as the country's 44th president, and the first African-American to reach the summit of U.S. politics. VOA's Dan Robinson reports.

I think the meaning of mark means "give a score". Am I right? I discussed it with my friend, but he thinks mark means "celebrate". So that I would like to make sure what’s the meaning of mark here.

Thanks a lot.

Maggie^^
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In my view,the more mistakes someone else corrects me,the more I could learn.
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[Mister Micawber]

.
Celebrate. "to notice or observe".
.
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Native English teacher at Mister Micawber's

[Maggie]

Thanks so much, Mister Micawber.

Maggie^^
_________________
In my view,the more mistakes someone else corrects me,the more I could learn.
And welcome to my blog: http://0rz.tw/793HL