Kidnapping started in the southern Nigeria as a means to get Government attention to degradation of people of Niger delta region. Now it has really gone beyond that as jobless people have hijacked it to their self-fish reasons.
What do you think is solution to this trend?

No doubt Government has been doing something concerning this according to some Nigerians (at least we meant to belief so through media). I don't think their best is enough as kidnapping is yet to be in reverse.

Who are their target?

Before it was oil workers, that is not the case now. As the issue that started the problem has been somehow addressed. But the question now is some people has seeing it as a business what engaging in.
What do you think is the solution to this?

Government needs to provide employment opportunities, this has been said many times. This is what they need to solve this challenge not sophisticated weapons.  

I think government in all level are worried and trying their best to curb the malady, and I see recently Nigeria law makers were proposing death penalty for kidnappers, I belief  with time it will be eradicated. 

It is quite shameful of the Nigerian government that Nigeria now accounts for 25% of global kidnappings. (See http://www.punchng.com/editorial/nigeria-as-kidnap-capital/)

Kelechi Okengwu is no doubt quite correct when he identified, in his study, the factors encouraging this shameful crime as  failure of the government to provide basic amenities, unemployment, the use of cults, gangs and militants by politicians in the electoral process and inefficient and corrupt security system.

Of all these factors, the one that clearly stands out is the politicians' involvement. If the government is serious about eradicating kidnapping in Nigeria, it must begin by withdrawing all the guns distributed by politicians to political thugs for attainment of their evil and selfish ends.

While inefficiency and corruption in our security system could also be blamed for encouragement of this crime, it should be noted that politicians' failure to equip  the security agencies with the right gadgets is another ploy to render these agencies inefficient in order to protect political thugs most of whom are now kidnappers.  

Except politicians are willing to solve the problem they have created, the law-abiding citizens have no hope other than to wait for the manifestation of the law of retributive justice in the lives of our politicians.

Ellisdo, Governments at all level have been upgrading security levels, by buying different gadgets and equipment, yet there are still kidnapping in Nigeria (though not they way it it use to be) but if government provides basic amenities, employments to the youth, encourage entrepreneurs among others this will go a long way eradicating kidnapping in Nigeria, as buying guns and equipment isn't enough as what caused the crime as you indicated in your post is still there.

great topic...like this most..