Believe me, I get asked the question in the title frequently and I have been thinking through the issues pro and con for some time now. The answer to the question is not as simple as saying, yes, you do need a desktop program. As a matter of fact, the companies that make only desktop computer programs probably have thought about this issue more than I have, but they are mostly ignoring the question in their advertising and presentations. Isn't it true, if you ignore a problem, it will go away?
For many people the distinction between a program that runs on their own computer and a program that runs entirely on the Internet is blurred or nonexistent. This is evident in the inability some have to distinguish between a "browser" and an online "search engine." I am frequently explaining that Chrome is Google's browser that works on your own computer, while Google Search is an online search engine. For many people the distinction is an entirely new concept. In fact, the idea that you can have more than one browser is a new concept to many people. Microsoft's marketing is so pervasive, they don't even realize that there alternatives to Internet Explorer. Likewise, many Apple computer users default to Safari without a thought to using another or a different browser.
If that type of confusion exists with a ubiquitous program such as a browser, think how much harder it is for some people to conceptualize the difference between storing your genealogical information on your own machine's hardware and having a program that stores their information somewhere unknown out there in the world of the Internet.
Until recently, I would have answered the question about whether or not to have a dedicated software program on your own computer with the obligatory, yes, in all cases and had a list of reasons for my answer. Now, I am seriously close to changing my mind altogether. Here is the question that comes up frequently that started the change in the way I look at where and how to store your personal genealogical information. Suppose someone has been doing genealogical research off and on for years (more off than on). Further suppose that the person started using Personal Ancestral File (PAF) back when it was the most popular program. Now, fast forward to today. People frequently approach me with questions about their genealogy and have all of their data in a PAF file. Their data is in serious danger of being lost either from using an obsolete program or from storing their data in an obsolete format. By the way, we are still having people bring in old data on floppy disks.
Now what if I have a program on my computer that automatically synchronizes my genealogical data to an online tree that I can access from any one of my different devices?
Now, what am I going to say to this person who has their whole genealogical research experience on PAF? Which of the fairly large number of programs do I encourage them to use? Do I let them know that there are several "free" alternatives to buying a dedicated software program and thereby set their foot on the path to constant upgrades and possible future charges for upgrades? Do I solve the problem by moving them to another program that they will likely not learn how to use and which will still pose a problem of compatibility in the future? Why not encourage them to put their file, their documentation (if they have any) and their other information online where someone else in their family can access it and work on it if need be?
Part of the issue is the question of whether or not it is reasonable to keep all of your genealogical data online? There are some distinct advantages to commercial online programs that assist in finding source material for your ancestors, but that is another issue. The question is, do you "back-up your data" to an online service? If you do or even if you should, why not keep all of your data online?
In the past, this was not a real issue. Backing up your file online was an option but not a very good one. There was no real way to work with a backup file. Now we have several very attractive alternatives in the form of huge, dedicated online family tree programs that have the backing of substantial organizations that are not likely to disappear where you can access your information from almost any device that connects to the Internet. Doesn't that constitute an alternative for the PAF user? Whether or not they make the next step and purchase a stand alone program to replace PAF?
Looking back, wouldn't it have been nice if my Great-grandmother had had access to the Internet and recorded all of her research, notes and sources online where I could have used them today? Aren't our children and our grandchildren going to wonder why we gathered all our data into an obsolete program that they cannot access in the future when we could have simply recorded all the data online and avoided the problem?
See, the answer to the question in the title is not quite as simple as it was just a few short years ago. Additionally, the answer to the question may become even more complicated as more and more people fail to see the need to learn to use yet another local genealogy program, when they are doing everything else in their life directly on the Web. Do you still think you need your own personal genealogy program? Oh, by the way, which one are you choosing and how long will it be around?