Ōkina otomodachi
Connotation. Many people in Japan, both otaku themselves and non-otaku, tend to think that it is allowed but not encouraged for one to be an "ōkina otomodachi", assuming that those works are for children, not for them. Adults who love children's books such as "Mary Poppins" or "Moomin" are not usually considered as improper, but the same is not necessarily true for those who love anime or manga such as "Mary Bell" or "The Star of Cottonland", even though they are similarly well-acclaimed fantasies. Commercial exploitation. On the other hand, some anime that seem to  be (mainly) for children are also (partly) aimed at "ōkina otomodachi". Fan service in a show that is supposed to be for children is often clear indications that it is also aimed at otaku. Many anime that are aimed at children are also—from a marketing perspective—created for "ōkina otomodachi", because the latter are the ones who have more money and actually buy expensive DVDs for themselves. The show may even have particular high-quality merchandise, such as figures, that is more specific to adult fans. Due to the decrease in the number of children in Japan, it is  not as easy as it was to produce a show purely aimed at children, and "ōkina otomodachi" is getting more important as a marketing target.