There is a feeling amongst many people that one is casteist if one marries within one's caste.
They ask "will you look for a son-in-law from ---caste?" or"look at the matrimonials" as a clincher in proving you are casteist.
I find that argument spurious. If I were to look for a son-in-law at all, I would definitely look for one in the families and social set up that I am familiar with. That way, I can find some sister-in-law's cousin whose husband is the third cousin of the son-in-law-to-be and then make enquiries about what the said person is like. But if my daughter were to find a person she likes and I, after getting to know him, find that he is a nice person who will make her happy, then I would not even ask about his caste/whatever.
Getting married, or shall I say the post of son-in-law is not an equal opportunity thing. Why will I not look for compatibility in as many ways as I can?