Please note the comments to this post for additional clarification on the International Genealogical Index.
Since the introduction of the FamilySearch.org Family Tree, adding sources has been a prominent issue. Presently, there are several types of "sources" that are showing up in the Source section of various individuals on the Family Tree. The first and most common categorization of the sources is the differentiation between sources originating in the FamilySearch.org website and those coming from outside the website. The source entries on an individual's Details page show two different icons reflecting the origin of the source information. Here is a screenshot show the FamilySearch icons that look like trees (sort-of) and the world icon meaning the source originates in another third-party website.
FamilySearch.org Family Tree are noted as having the "Title Unavailable." That is another one of the program errors. These were validly attached sources from FamilySearch, but for some reason they are no longer linked in a way to insert the title to the collection. My guess is that the titles will return sometime in the future.
The next category of sources is called "Legacy NFS Source." Here is a screenshot:
This particular source brings up a number of questions. The information in this entry came from a "user-supplied" source citation. But this entry also points out an important fact about the sources being added to the Family Tree. Not all of these sources are, in reality, sources. In this case the information came from another user-supplied source: The Ancestry.com One World Tree. Incidentally, the information is inaccurate. San Bernardino County did not exist in 1852, so Henry Martin Tanner was actually born in Los Angeles County. An online user-contributed family tree is not a source.
Another type of source that is showing up in the Family Tree is the "Extracted IGI Record." Again, this is not a real source, but merely a FamilySearch mechanism to notify users of several issues with the data. I wrote about this situation in my last blog post and there are some helpful comments about these IGI records. Here is what an IGI extracted record looks like. Again, the title of the record is missing due to some FamilySearch issue.
The idea here is provide adequate supportive links to documents or records that provide information about your ancestor. Every source record should be examined and evaluated for the reliability of its content and then entries added to the person's details reflecting the information in the source.