Why does Yahoo answers allow a question to be asked multiple times on a daily basis?

Because Yahoo has zero interest in running this site. This is obvious by the way they have made changes that only encourage trolls and refuse to make corrections to reign in unacceptable behavior here. Currently the only way to get action taken to eliminate truly offensive people here is by gaming the system here to artificially raise your trusted member status and even then the people here posting abusive content only create another account or 3 to continue doing the same things over and over. You don't have to look hard to find all kinds of corroborating evidence to support the assumption that Yahoo is getting ready to cut and run from this site completely. If they actually gave a **** about this place they would have at least fixed the name/avatar picture problem by now. I don't expect this site to be up for more than a year more at most.

Some are spam bots some are trolls some are OCD people and some are ones that the person doesn't think have posted and keeps posting. YOu can report many of them.

They don't 'allow' it,but it does happen.Mostly the person doing it has an obvious mental problem but it can be spam as well.It's up to members to report spam.

So more people can see your question there is always slow days