Isn't that really the point of attribution? You are borrowing someone else's words or pictures. You may not be able to "put them back in the same spot," but you can send others back to the spot where they were found.
Too often on Twitter and Facebook I will see something that I know I have seen before. Almost invariably I do some digging and I find the original news article, blog post, or image that it came from. Sometimes it is in a re-tweet (RT) and the person who originally tweeted it is the guilty party of not giving credit where it is due.
So, what should you do before you re-post something? My immediate answer may surprise you after my intro here. I say it depends. If you are in the middle of a twitter chat where 50 to 100 tweets are flying by every minute, then you may miss hundreds of tweets with great nuggets by researching that one tweet. Just favorite the tweet prior to RT'ng it and then you can go back and give the original item the proper attribution after the chat.
If, on the other hand, you are seeing a tweet outside of a chat or in a slow moving chat then take the time to check it out and if the original person wasn't mentioned in the tweet take the time to include "via @originalperson" in your RT. If you need to modify the original tweet prior to RT'ng it to fit the "via," then remember you are now tweeting a Modified Tweet (MT) not a re-tweet. Just use MT instead of RT and everyone will know what you did.
Finally, if you are going to be the original person putting something up on Twitter or Facebook, then take the time to craft your tweet or post so the attribution is included. If you can't find the person's Twitter handle through the twitter search do a web search using the person's name and the word twitter - "chris fancher twitter" for example.
If that doesn't immediately give you what you need, then research where this person works. Is he or she with a business, at a school or university, or in a school district? If nothing else find a twitter handle for the specific place of employment and include that.
Take the time to do the simple task of giving recognition to the originator of whatever "tool" you are using. You owe it to them and to your followers to do it right.