FamilySearch.org Family Tree may also start providing such automatic suggested links to sources. Right now, FamilySearch.org's Family Tree will search for sources but the user has to instigate the search. However, in the descendancy mode, Family Tree will suggest sources for selected individuals. Because of the nature of FamilySearch Family Tree, there is no need to suggest connections to other family trees because the program is a unified family tree. Although Mocavo.com hosts family trees, it suggests sources only, so far. But it does suggest that you join a "surname" group for individual connections. It should also be noted that Geni.com is owned by MyHeritage.com and uses some of the same technology.
As far as I am able to determine, Ancestry.com was the first to automate the process. A significant advance in accuracy was released by MyHeritage.com in 2013. Because of the complexity of this type of matching, many of the programs are surfeited with "false positives." This means that a suggested connection or source is attributed to the "wrong" person. For example, your ancestor lived in New York and the sources or connections are to people living in other states or even other countries.
Because of these false positives, there are recurrent questions about this practice that fall into two general categories. First, the questions involve the accuracy of the suggested sources and second, they involve the number of suggestions.
If you are not familiar with this particular type of feature of any of the above programs, you should be. By and large, these types of automated source and family tree connections are extremely valuable aids to research. Each of the programs listed above (with the exception of FamilySearch Family Tree) host multiple (millions of) individually submitted family trees.
If you have a family tree on any one of the above programs, you are likely receiving notifications of suggested "matches" to sources and to other family trees. In some cases, the number of these notifications can be overwhelming. For example, right now on my Ancestry.com family tree, I have only 326 suggested sources these include connections to other user submitted family trees. However, this number has been over 1000. On my family tree on MyHeritage.com, I have 501 Smart Matches to other family trees pending and 7096 pending Record Matches to sources. In addition, if I click on any of the Record Matches, I will have many more suggested sources.
The accuracy of these particular programs, Ancestry.com and MyHeritage.com are very high. It is very difficult to compare the two programs because they have different sets of source documents and the suggestions do not overlap except when they both have the same source.
Depending on the individuals in your own family tree and whether or not the source documents in any of these programs apply to your particular ancestry, you may or may not have this type of response to the automated search and tree matching functions. But in many cases, the response to your family tree is overwhelming. How do you deal with these huge numbers of sources and connections?
My answer is simple, ignore them. There is no reason to feel anxiety over the fact that there are so many sources and connections available. Use the programs as a tool for your own research objectives. If you have the objective to add sources to all the individuals in your family tree file, then do so. Work through the suggestions systematically but realize that the programs will always suggest more than you can handle. On the other hand, if you wish, you can focus on individuals in your family tree and if there are suggestions they might be helpful, but if not, then you are in a waiting mode. Remember that these programs all add new collections and sources on a very regular basis. You may not have a suggested source for an individual today, but that could change tomorrow.
What if you want to use these programs to do your own research and not use their automated search and matching? You can, of course, do this but then you are basically wasting your money. These programs are designed to do the work for you. If you do your own searches, you are not using the full potential of the programs. You must have uploaded a family tree and you need to allow the programs to make full use of their potential.