I checked -- it was not new syntax in 10. I think it's been available for quite a while.
You can use select together with a selection condition to extract rows by content. For example, code below uses a pure function that returns True for a particular match. A row is selected if the 2nd column contains precisely "B"
In[6]:= set = {"A", "B", "C", "D"};
In[7]:= data = RandomChoice[set, {9, 5}]
Out[7]= {{"D", "D", "B", "C", "A"}, {"A", "C", "A", "A", "C"}, {"C",
"B", "D", "B", "C"}, {"B", "A", "A", "C", "C"}, {"B", "B", "A", "B",
"C"}, {"B", "C", "B", "B", "C"}, {"D", "D", "B", "D", "A"}, {"D",
"C", "D", "C", "D"}, {"A", "A", "C", "B", "A"}}
In[8]:= Select[data, #[[2]] === "B" &]
Out[8]= {{"C", "B", "D", "B", "C"}, {"B", "B", "A", "B", "C"}}