Multiple threads with same topic is one of the major reasons of spamming on this forum,  majority of the members don't use "search" before creating a new thread.

I am wondering that if admins can add an automatic "search" feature in the creation process of new thread, it can help to minimize the amount of similar threads.
Like if i have to post a new thread with subject " Honesty is the best policy" i have to go through an additional step when i click "post", the forum automatically search my subject in that section and display topics with almost same subject, so i can check if my topic already exists or not.

If there's an existing topic and you've came up to that kind of content, it doesn't mean you're not allowed to create a thread with similar topic. You can do revisions and development to the existing topic with more attractive ideas.

If the the body of the thread is just a basic information about a specific topic, you can do revisions and make an extraordinary contents and will make viewers understand the whole system. Topics can be repeated but the content itself can't because that's the part where you can state your opinion and ideas regarding to the topic, right?

As you can see here, multiple threads that has a topic of "merit system" but has different explanations and meanings. Many people has a topic of "ranked up members" but has a difference on how do they present it and many more. In real life, thesis also have revisions and similar topics are used but being developed to say it's a new thing.

That would be a cool and usefull feature, https://stackoverflow.com uses it and even though sometimes is not catching exactly what you want, at least make you think if it's worth openening a new thread or question.

People can use Google Search.
Most answers on my question I found using Google and it shows me many threads on bitcointalk.
People are lazy to do that

Yes, you can do revision and development but most of the times they are just duplicate topics.
The main objective is to pass members through review step, so he/she can review if their topic is significant or they are just creating additional thread of same topic which is useless.

Thanks not a bad idea, malikusama. I have seen this feature on a lot of other websites.
I think this could be included in the new forum software (beta.bitcointalk.com) features proposals.

I'm also using Google search because it's faster than searching the forum. The down side is that it take a few days for the google bot to crawl new pages created here so you might not see all of the posts (especially the new ones) in your search.

You didn't understand what i said, i know there is no auto search feature that's why i made this thread.

Good idea, can use the related topic suggestion when the poster wrote Subject of new topic 

This a good idea. Maybe this way we could encourage users to search first or at least make them to check the suggested threads before allowing them to post.

I'm also familiar with what stackoverflow's process of submitting a post and I think it could work here too

not a bad idea, but I'm not sure how feasible.
what if someone makes writing error enough to search can't find a thread with the same subject?
Most of the duplicated threads come from the marketplace and altcoin discussion section, where the signature hunters post his shits. it's better to disable signature in this section, it would certainly have made a less number of double thread.