What does the cryptic crossword clue "Change in some online ad, lacking in depth? (3,11)" mean?

The wordplay uses an anagram. anagram of IN + SOME + ONLINE + AD, = ONEDIMENSIONAL The answer is ONEDIMENSIONAL.

Change in some online ad, lacking in depth? (3,11)

Daily Mail Cryptic #17397 | 6 Across | 2024-07-09 flower