why do christians come on here and ask for other people to pray for someone? isn't one prayer good enough?

same reason banana clips are so popular?

These wouldn't be the same Christians that constantly bash Catholics for asking saints to pray for them, would it?

Because that would be ironic.

Your view of prayer is narrow.

Christianity is wholistic, not some modular thing that you can just use pieces of.
That being said, prayer is a part of Christianity wherein God wants us to have lives of more than just demanding things to be done but rather coming together in community and doing something about what we are praying about.
It is far to easy to talk to God about people, but more difficult to talk to people about God.

In a way, coming together brings community and as Christ said that if they gather together in his name, there He will be also, in this line of reason, God may grant the prayer by means of the people already present and inspiring them to be more selfless and finally do something about what they are praying about.

We are the body of Christ.

James 5:16 Tells us to pray for one another. The same verse also says that the effective, fervent prayer of a righteous man avails much.

Paul had no problem asking other people to pray for him.
1Thes 5:25 Brethren, pray for us.

Bottom line: There is power in prayer. If it were not so, the devil would not be working so hard to make it illegal.

God hears our prayers

1 Then he told them a parable about the necessity for them to pray always without becoming weary. He said,
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"There was a judge in a certain town who neither feared God nor respected any human being.
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And a widow in that town used to come to him and say, 'Render a just decision for me against my adversary.'
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For a long time the judge was unwilling, but eventually he thought, 'While it is true that I neither fear God nor respect any human being,
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2 because this widow keeps bothering me I shall deliver a just decision for her lest she finally come and strike me.'"
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The Lord said, "Pay attention to what the dishonest judge says.
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Will not God then secure the rights of his chosen ones who call out to him day and night? Will he be slow to answer them?
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I tell you, he will see to it that justice is done for them speedily. But when the Son of Man comes, will he find faith on earth?

More prayers in faith, help have prayers answered more easily.
The scripture that says where 2 or more are gathered together in my name. I am in the midst of them.
So in essenece God will speak at times as well.
I perceive your thoughts reflect some perhaps not believing what they ask as a possibility of lack of faith in what is being prayed about.
Some issues are prayed about jointly for speedier answers of urgency like sickness, illness, deliverance or issues that we feel overwhelmed about.

Maybe christians understand that the odds of your your prayer being answered are only 50%. Perhaps they try to get more people praying to increase their odds.

its called community and moral support...

The Bible says the more the better.

Jesus said where two or three are gathered in My name there AM I in the midst of them.

I think you are missing the point that this is a section for people who pray.

I bet you thought it was a section for beauty>>?

The more the better. It has been proven

Five more days until church. They can't wait that long.

I do it all the time. So does many of my friends. If it gets the prayer requests out to others to help build up the prayer line then so be it. There are groups of people who are also called prayer warriors, they are always praying for others as well. I use the computer and the ones who has no computers then I call and ask for prayer. alot of times the people who are in the need of prayer can't pray, maybe sick on their death bed, or in an accidents, who will pray for them? Others.

Far as I can tell, it seems to be quantity not quality that counts..

may be they are looking for ones with more faith and the more the happier but its good to help Consul each other like Christ did when his friend lazerith died he wept with the family