Short answer

=TRANSPOSE(
   QUERY(
    TRANSPOSE(
      IMPORTXML(
         "http://chat.stackexchange.com/transcript/7/2015/8/13",
         "//div[@class='content']"
      )
    ),
    ,
    1000
   )
 )

Explanation

IMPORTXML is returning an array having one column by each inner span tag. There is one span tag by each smart link included in the chat message.

"It's known" that QUERY joins the headers rows. As in this case the OP wants to join rows, the formula includes TRANSPOSE two times, the first to be able to use the QUERY behavior to join columns and the second to return the array to the original shape.

Reference

• Answer by JPV to Google sheet arrayformula join() and split() functions

based on your question I assume your data looks like:

where you can drop the whole side calculations by having:

• cell D10:

  =SUM(SUMPRODUCT(OR(COUNTIF(B3;"<>"); COUNTIF(B4;"<>")));
       SUMPRODUCT(OR(COUNTIF(B5;"<>"); COUNTIF(B6;"<>")));
       SUMPRODUCT(OR(COUNTIF(B7;"<>"); COUNTIF(B8;"<>"))))

• or cell B10:

  =SUM(IF(OR(D3<>""; D4<>""); 1;);
       IF(OR(D5<>""; D6<>""); 1;);
       IF(OR(D7<>""; D8<>""); 1;))