I spent years compiling my ancestry. One of my (friends, cousins, someone -- insert the name or description) asked for a copy of my file. I sent them a copy and later found the file on their Website (Blog etc.) without any acknowledgment and claiming that it was their file.I call these people who steal others' information and present it as their own, data vampires. Personally, I am very liberal in sharing my data files with any interested family members. But I can certainly understand the feelings of someone who has spent a considerable time working on a family line only to have some one else claim the credit.
Another variation on this theme is developing in the New FamilySearch program. I am more and more frequently hearing the complaint that people are reserving and doing ordinances for people who are entirely unrelated. Formerly, I am aware that this is and was commonly done, but now because of the ability to see the process in action, people are becoming more and more aware of the practice. As a side note, I can watch my own family's data files change on New FamilySearch from week to week with more and more duplications and wrong information.
The data miners do not care if they are not related to the people they claim, neither do they really care anything about the identity of the people as long as they can add more names to their file and print more Family Ordinance Requests and get a huge stack of cards. The motivation seems to be driven more by acquisitiveness than by any motivation to do family history. I have personally seen data miners with boxes and briefcases full of LDS ordinance cards, hundreds of them, if not thousands. As long as they can click a green arrow and print a card, that is all they care about.
I had an opportunity to look at a pile of cards recently and it was abundantly obvious that the names were in no way related to each other or even accurate to the point of being realistic. One example was a card that had an individual with an English sounding name and a birth date of "ABT 1800" in Texas. That was interesting to me because the first American settlement of Texas occurred in December of 1821. Many of the cards in the same batch had no birth date or birth place. I understand that the latest revision of New FamilySearch will not allow cards to be printed for individuals without at least a birth date and location, but here were a number of cards without either date or place.
Data miners indiscriminately gather data without regard to either relevance or accuracy. The damage that they do is that some people believe that they are actually doing genealogy or family history, both the person printing the cards and others who are impressed with the numbers. Obviously someone who has printed a thousand ordinance cards is doing a lot of research and genealogy!!! The data miner is really just indiscriminately copying others files and information, without regard to reality, historical or otherwise.
When you combine a data miner and a data vampire in the same person, you have a really dangerous individual. Someone who, by their bad example, can discourage whole generations in a whole family from actually doing any real family history.