I got my 10-year US visa type B1/B2 on 13 Feb 2013. Shortly after, when entering the US, the CBP officer wrote B2 13 Feb 2014 with an ink pen on the passport page next to my visa.
What does this note mean? I was not given any explanation, nor I had problems entering and leaving US back then.
The notation is normally written on top of the CBP stamp that indicates when you were admitted to the US. The stamp has two blank lines, one labeled class and the other labeled until.
The notation indicates that you were admitted in B-2 status ("class"), until the 13th of February, 2014. That notation concerns only your first entry. After you leave the US, when you enter the next time, you'll get a new stamp with a new "until" date. With each entry, the class will either be B1 or B2, depending on the purpose of that trip as described to the immigration officer.
