There is a posting dated April 14 at Roberta Estes DNA eXplained blog that I hope everyone new to family history research and DNA will read and take to heart: DNA Ancestors that Aren't aka Bad NADs
http://dna-explained.com/2015/04/14/a-dozen-ancestors-that-a...Roberta not only explains the drawbacks to ancestry's New Ancestor Discoveries, she relates it to the drawbacks of merging other people's family trees with your own. If you do this you will end up with a huge mess to clean up. As she points out, and it cannot be stressed enough, just because there are hundreds, if not thousands of family trees out there that state John Doe's wife was Mary Smith daughter of Joseph Smith, does not make it so. Trees are copied over and over, carrying over the same errors, and if you don't do some serious digging you may not get to a tree that has some correct info, if it exists at all. Looking for a tree that has the most sources will not help, because ancestry counts other peoples trees as sources). Other people's trees are NOT sources. They should only be used as clues to find sources. Often there is no actual source at all, the connection is just someone's assumption/guess work stated as fact in a genealogy book (if it's written in a book it must be right!), perpetuated over and over and over..... Roberta talks about all this, and I've found it out myself many times. I've gotten through a number of brick walls by questioning other people's trees, books, etc., hunting down original records. We all make mistakes as we research our ancestors, even the most experienced researchers. That's why it's important to keep revisiting the various branches of our trees, looking to see if they make sense (e.g. we don't have an ancestor marrying after they died), and to see if we can find more original records that may change our interpretations of circumstantially based family connections. Once you put wrong/bad info in your tree you are very unlikely to get "hints" for correct info/records. Keep searching independently of your tree. Do not rely on ancestry's "hint" system to help you find your true ancestors.
(OK, getting off my "soap box" now....)