A GEDCOM file is plain text (usually either ANSEL or ASCII) containing genealogical information about individuals, and metadata linking these records together. Most genealogy software supports importing from and exporting to GEDCOM format. However, some genealogy software programs incorporate the use of proprietary extensions to the format, which are not always recognized by other genealogy programs, such as the GEDCOM 5.5 EL (Extended Locations) specification.Even back in the time when GEDCOM was commonly used to transfer genealogical data between two programs, the process produced an "error" file with information that could not be copied. Over time, the information that is not transferred has grown as programs implement features that are not supported by the old GEDCOM standard. I have discussed the use of GEDCOM or mentioned the problems associated with using GEDCOM to transfer genealogical data in at least 20 previous blog posts.
Let's suppose that you are using a program on your device that stores genealogical data. For whatever reason, you do not trust the "internet" or "cloud" to store your data so you eschew the use of any online programs such as the FamilySearch.org Family Tree, Ancestry.com, or MyHeritage.com. Let's further suppose that you have now entered a huge corpus of information in your program. For some reason, you now start to worry about what might happen to all your data if your computer crashes or your program is discontinued. You also decide that you should "share" all your work with your family. What do you do to share your information? How do you back up your data?
Let's further suppose that you contact your family and offer them copies of your data files. You are surprised to find out that none of them are using the program where all of your data is stored. In fact, none of them have even heard of the program. When you decided to buy all of them a copy of the program you find out that the program will not work on any of their devices. So, you decide to export all your data in a GEDCOM file which you share with all of your family members. None of your family members know what to do with the file.
This hypothetical example could go on but in the end, no matter how the example is written, the results are the same: the information on your computer is lost. Even if you were successful in having someone in your family accept the information in GEDCOM format, it is very likely that much of the value of the information would be lost. For example, GEDCOM does not parse sources. What this means that if you use a program that allows you to enter a source for your information, GEDCOM may lose the information or end up putting the source into one long line of text. The program creating a GEDCOM file and the program receiving the GEDCOM file have to match the way the data is coded by the GEDCOM standard. As the description states above, "However, some genealogy software programs incorporate the use of proprietary extensions to the format, which are not always recognized by other genealogy programs." This was always the case with using GEDCOM to transfer genealogical information. If that was true twenty years ago, it is even more of a problem today.
Unfortunately, the problem of transferring accurate data between programs is still a challenge today. There is still no common standard for transferring data from one program to another except for some residual support of using GEDCOM. If you don't mind losing a significant part of your data, GEDCOM is still in use and still being promoted as a "solution" for exchanging data. However, some significant progress is being made. For example, FamilySearch.org and MyHeritage.com have developed a synchronization program that will allow the exchange of all of the information of at least 8 generations of the data in either program. However, this process is presently limited to those who have FamilySearch Accounts and are members of The Church of Jesus Christ of Latter-day Saints. There is also a limited way to exchange data between Ancetry.com and FamilySearch.org also limited to members of the Church. Perhaps these initial efforts will expand and allow other programs to share information. There are also two desktop programs that have the ability to exchange source information with online programs: RootsMagic.com and Ancestral Quest (ancquest.com).
If you are starting out with your genealogical research, you may wish to consider the ability of the program you choose to use based on the program's ability to transfer data to other programs.