There is one advantage, however, in the small state, the city, or the village, which only the wilfully blind can overlook. The man who lives in a small community lives in a much larger world. He knows much more of the fierce varieties and uncompromising divergences of men. The reason is obvious. In a large community we can choose our companions. In a small community our companions are chosen for us. Thus in all extensive and highly civilized societies groups come into existence founded upon what is called sympathy, and shut out the real world more sharply than the gates of a monastery. There is nothing really narrow about the clan; the thing which is really narrow is the clique. The men of the clan live together because they all wear the same tartan or are all descended from the same sacred cow; but in their souls, by the divine luck of things, there will always be more colours than in any tartan. But the men of the clique live together because they have the same kind of soul, and their narrowness is a narrowness of spiritual coherence and contentment, like that which exists in hell. A big society exists in order to form cliques. A big society is a society for the promotion of narrowness. It is a machinery for the purpose of guarding the solitary and sensitive individual from all experience of the bitter and bracing human compromises. It is, in the most literal sense of the words, a society for the prevention of Christian knowledge. - G. K. Chesterton, Heretics, Chapter XIV
Thus the very thing that gives joy to many, including me, about the Internet, the availability of specialized, congenial social groups, is what is wrong with the Internet, according to the Chesterton. Chapter XIV of Heretics is an argument in favor of the moral importance of social groups--such as the family--whose membership we do not choose. It is, thus, an argument in favor of random associations. For in such groups we must simply bear with people--and, oh, how much sometimes there to be borne--whom we would not have chosen to be with, and this broadens the mind, pulling us out of complacency.
I have earlier argued that there is nothing wrong with arranged marriage. But Chesterton lets one go further. The very thing that people object to about arranged marriage, that it does not let one choose someone congenial to oneself, is its value. A marital selection based on congeniality lets each minimize the amount of required change and growth. But an arranged marriage, where a match in religious views is ensured by the parents, but otherwise personality characteristics may be wildly different forces one to broaden one's mind, at least in contexts that do not allow an easy way for the spouses to separate (of course, it is important to allow separation in extreme cases, such as abuse, even if remarriage is wrong).
This advantage is not very great, because the closeness of association in marriage is such that even in a love match, the negative, self-congratulatory effects of congeniality are mitigated by the myriad of differences, and sometimes annoying similarities, that one had no way of knowing about, and that make for growth as a person. Moreover, marriage itself changes a person, and so what one knew about the other prior to marriage will in part be irrelevant, thereby making a love match somewhat more like an arranged marriage.
This is not, of course, a blanket endorsement of marrying people who are utterly different from one. Congeniality in itself may not be so valuable, but if one is going to marry, one should marry someone with a modicum of virtue and moral sensitivity. Moreover, one should already have developed some virtue and moral sensitivity oneself to be mature enough for marriage. So there is a similarity in the fact of the possession of virtue, valuable not because of the similarity but because of the virtue, that it is good to have. Moreover, it's probably not a good idea to marry someone who is so far uncongenial to one as to impede moral growth, by changing love to disgust. And so on. At the same time, the evidence that a practice of love matches is better than a practice of arranged marriage at avoiding these problems is weak.
Finally, it must be reemphasized that the above defense of arranged marriage only works in contexts where it is not easy to separate from one's spouse, or where at least there are significant costs of such separation, such as a lifetime of sexual abstinence (as in the case of Christian marriage, where it is permissible for spouses to separate in circumstances of abuse and maybe even adultery, but they remain married in fact if not in law, and hence cannot marry anyone else). Chesterton talks of how scary it would be to be snowed in one's street. What is scary about it is that one would be forced to socialize with people one had not chosen for oneself. But it is essential that there be an element of forcing here--that one be stuck in marriage.
The above considerations give a powerful response to the following sophomoric argument: "If a couple really loved each other and were really compatible, they wouldn't need marriage. They would just live together, and their love and compatibility, rather than legal ties, would keep them together." Moral transformation hurts. Patients whose are not anesthetized need to be restrained for operations. If the couple is always compatible and their congenial love is sufficient, without commitment, to keep them together, then it is very unlikely that the members of the couple are being morally transformed by their closeness. Thus, leaving aside the case of the already morally perfect (and they might as well be celibate for the sake of the Kingdom of God), a couple is either not going to be transformed significantly by a life-long relationship or else there will be strains that require one to be held down, to be snowed in.
Let me end by noting that perhaps the most serious problem with arranged marriage is that, I think, it tends to be found in cultures where there is a strong pressure to marry. It is important that the marriage commitment be undertaken freely. This is compatible with the parents' choosing the marriage partner, or giving one a short list, as long as one is free to reject them all, free to remain celibate.