this is a habit some people have to block their posts from being searched.
on forums such as this, its not so bad
but on a forum like the one at DPreview, something out of the stone age, with a horrible search algorithm, by writing n*k*n instead of nikon, when someone uses the keyword "nikon", the pentax related thread wont pop up.
sort of a self policing mechanism to help others use the search function.
otherwise if a nikon user types in "good nikon lens", all the pentax threads with the words "good" and "nikon" will get thrown in the mix, without realizing that half of them could be "my pentax is sooo good, nikon sucks"