Rebol - 206
==========
Parses the html using the `parse` sub-language of Rebol. Checks the first 15 pages (ignoring errors).

    z: collect[parse reform collect[repeat n 3[keep read join http://stackoverflow.com/questions?sort=featured&page= n]][some[thru{n">+}copy x to{<}(keep to-integer x)]]][c: c + z/1]x: 0 forall z[x: x + z/1]x

**Test**

    >> z: collect[parse reform collect[repeat n 15[keep read join http://stackoverflow.com/questions?sort=featured&page= n]][some[thru{n">+}copy x to{<}(keep to-integer x)]]][c: c + z/1]x: 0 forall z[x: x + z/1]x 
    == 18000