The most common and most likely answer to this crossword clue is the 3 plus 3 letter word DOT COM
I've seen this crossword clue in Independent
D
O
T
C
O
M
Buddy explains!
The straight part
We know that "Sort of business" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sort of business = dot com.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DOT COM mean?
DOT COM noun- A company whose business is based around a website or primarily via the Internet.
- To convert to using or being based on e-commerce.