If you wanna do it for more than one, use not in, it's more intuitive than not or/ands.
select * from table where category not in ("News","123");
Drop the not and you have the opposite.
Note that I think you can now use sebselects in in() constructs in MySQL now, so you could do something like:
select * from table where category not in (select category from table group by category having count(category)>2)
kinda thing.