"Sir, if all evidences are removed on purpose or by mistakes or by turn of the time, how can you prove your contribution?"....Asked by someone.

"Sir, if all evidences are removed on purpose or by mistakes or by turn of the time, how can you prove your contribution?"....Asked by someone. 

There are several points to this answer:
1. None. No one can contribute something permanent and leave his/her name forever.
2. Even if the URL's are removed, I know what you are pointing to, still the contribution done is recorded somewhere. E.g. I kept raising question for the welfare of all on the UNO/ world bank websites. Then collected it and published a book with ISBN. Now half the URL's are not been seen, but, ISBN and several libraries of corporate and institutions hold the records with clean efforts. Thus, at least till year 10000 A.D. ( Y-10K) the contribution will be remembered, same is the case with all other research publications of others, and about the other fields, God keeps all the records.....If at that time the problem of Y-10k occurs and the systems collapse, then, God knows, thus proving....none and nothing is permanent. However, till we live, we live for others and together we live.Also, never in the human existence we humans were so near in planning Millennium Development Goals (MDG) and still we are so away from achievement of them.... Still.... we are trying our best .....hence I raised these questions boy...I think it's possible...MDG are possible goals for human kind....
3. What you pointed is also true. Like Ramayana and Mahabharata and Upanishada to make something remembered forever, you need to create something like that.
4. One of the counter point to First / 1st point is, there are few like Ram the great, Krishna the great....lives in the heart of people forever.
5. Your point proves one more fact that, the unknown contributors are infinite and than the known contributors who are by default finite. By default also, true contributors lose their name once the leader is someone else than the real contributor. Ex. There are people who are doers and there are people who believe in pomp and show off and taking credits. There are few who like to do and show as well. So there is a mixed lot everywhere in the world. However, let's keep contributing as God knows who is who.
6. One more point is, people feel someone is doing something but it's God who gets his work done from someone or group of people or from that particular generation and it's his contribution if you realize. Otherwise, not even a quark leave atoms and photons, yes even a smallest particle cannot move without his wish. As Saint Tukaram said, "Vrukshachehi paan haley tyachi satta". (Marathi). Meaning, "Each leaf and the leaves on any tree moves only at the wish of god. Thus anything that happened/ happen and will happen, it will be His i.e. God's wish." Hence, if you believe in contribution keep contributing, and leave rest to almighty.
7. At the end it's the name that's the most significant identity of a body that differentiate from others. If even the name is gone, then, none can identify anyone. On this only all the spiritualists worked and came up above all there senses and attained the spiritual enlightenment, they lost their identity and merged their small soul into the Almighty's soul. However, the fact remains, they had to lose their identity to merge with Almighty (God). However, the world still knows them by their identity that's by their name only. That's the fantasy of this world. One loses everything for almighty and almighty holds back everything to the person again just because of this identity of his/ her name. God is also proud of his children.....sometimes he himself expresses himself in the form of body....entity...though he has no identity at the same time has all the identities.....it's beyond words and dilemmas and worldly things. So, let's leave it to him, let's contribute first and leave everything to God as it's his wish that's driving us.
8. Let's work harder, smarter, and for welfare of all than for selfies motives to gain something, then, may be the contribution will be remembered by this world.
9. One of the finer point all the spiritualists and avatar and saints pointed out is that it's the name and fame and the money and the family, that bounds the man/ woman a lot, and if we can get rid off this craving for these, one can remain out of the bonds. Though our body is associated with our name, and we try to prove all the times that I'm the best or not guilty or this and that.....better we contribute without any expectations as put up in Geeta by Lord Krishna. Thus, if we keep contributing better than the best and better than our previous contributions, then one day we stop thinking about all these things and keep contributing for the welfare, safety of human kind.
10. Also, if you try to be famous or the best contributor, then you lose the focus of contribution to society, as it becomes the work with intention of becoming someone....God is against all these things. Keep contributing....there is joy in giving...self sacrificing....empathy....contributing....seeing others happy...investing in positivism and positive change...even one life is changed for good our life is done....nothing left to contribute....but still go on contributing...relentlessly....tirelessly ....without asking anything from anyone...that will be great contribution and we'll be one among those great contributors who have vanished from the records of the world but we could made a small to micro to delta to nano-scale to quark scale difference. (This 8th thought came to my mind at early age of my life....and it's great feeling....to work selflessly for this world. I was advised to do something great everyday, at least 1 good deed that changes someone's life. Everyday.)
11. There are many theories and practices, where in people keep contributing but keep their name unknown to the society due to very many reasons given bellow:
i. There are few, like Dadhichi Rishi, who sacrificed his life to get the Vajra for Indra, who sacrificed himself for the greater cause, they felt it's thebest way to contribute to society at large,
ii. There are few who say, if one person sacrifices for the society at large, it's better, next level is if one family is sacrificed in place of bigger section of society it's better, next level is one village, next level is next city....etc. Thus, in past, present and in future too, such people who sacrifices were and will be there. They feel by doing this, they are keeping the man kind become immortal on earth.
iii. There are a lot of people who do lot of hardship and sacrifices a lot in the name of classified acts for the nation. Who know about them?
iv. There are lot of people who do lot of hardship for their own family, who know about them?
v. There were lot of kings and their soldiers who did a lot for their kingdom, who remember their name?
vi. There were a lot of people who on purpose sacrifices a lot as they believe there is more gain in giving than taking.
vii. There are few like Kunti the mother of Pandavas, who asked and requested for sacrifices, for the hardship, and demanded pains and sorrows from the God, as she had habit to remember God in such situation only and she wanted herself to be in the remembrance of god throughout her life in which she felt the salvation.
viii. There are many Saints who sacrificed for the people at large.
ix. Jesus sacrificed so that humankind could live and survive.
x. Ask your mother, she will feel happy in spending a whole night changing your nappies when you are dependent neonatal baby. Some people like to sacrifice their name and fame and become an unknown entity like that.
xi. Some propose to advertise or forward name of their Guru or God or Goddess though they work hard and give the credit to them. By doing this they feel the sacrifice of their name and fame and feel true devotion in it.
xii.  There are few who tried to control the whole world like Ravana, and other known and unknown kings or .....but, they could not. No-one lives forever with physical body, those who are immortal are due to their sole soul contribution only.
xiii. Also, there are few who have sacrificed and have taken sanjivan samdhi and come to help their devotees and in India list is very big.
xiv. Some philosophers, and seers do lot of hardship and offer lot of services to mankind but keep their name secret as they believe it's the last thing attached to body and if someone knows the name they might not get mukti/ nirvana/ moksha / salvation if someone call them, remember them by name.
xv. There are many who put their name on every possible daily, every possible name plate, every possible website, every possible domain will they be remembered forever? There will be always a persons who breaks the records.... Thus, it's a continuing world and stops for none. May it be avatar or saint or family or what ever may be....this world goes on forever...then why worry about our own name and fame and this and that...just keep contributing and live it to God.
So there are many theories and practices.
12. Just keep in mind, in 1800's there was industrial revolution.  In 1900's there was ....revolution...in 1990's to 2015's ...revolution....thus, on the societal front many such tsunami and floods occur and the contribution of that particular person is taken more seriously being the existing in front of the eye. Hence, sometimes past contributions are forgot. ...Also there is nothing greatest in this world that's record has not been broken, so superlative word becomes minuscule when it comes to contribution....to this world or any other world....there will be someone better always and ....there is no end to it, and this world goes on like this only....So child...let's do work of God...every moment...everyday till the end of the life..... Hope you remember....the Samarpan to God....by offering everything we have....we're going to contribute....

"Whether you hate me, whether you love me, I'm going to contribute, contribute, contribute. ....as it's for the welfare of all and for the benefit of all...."

Aum. Amen. Amin. 

Dr. Ashish Manohar Urkude, lives on the ground, Nagpur, India.