What for these abbreviations "4u", "2u", "c u"?

Well, I just cannot understand how much time one saves by abbreviating words like these? To me, it is just an effective way to demonstrate luck of originality...when I am in a super hurry, I use them in cell texts (with a guilt feeling), but why on e-mails, isn't it extra important to show intelligence, seriousness and sincereness by spelling out words in this kind of site...or is it me who has to adjust myself to the year like 2011!??

Cheers,