I will have been on WikiTree for 2 years on May 15.
My dad put a lot of time into tracing out his cousins (his father was one of 11 children) and keeping in touch with them. I remember helping him to set up his notes in a flat-file DOS database called File Express.
Dad died in 2005, but I kept a copy of his database for years, meaning to start working on it myself "when I have time", which probably would have been "never" if I hadn't seen A.J. Jacobs' TED talk about the Global Family Reunion. So I decided to get out Dad's database and do something about it. The next question was: "how?"
I looked at free-standing genealogy software, but the Mac options I found didn't look terribly inspiring, and besides, I didn't want to keep this stuff in yet another silo for somebody else to dig into (or not) after my death.
Jacobs recommended Geni, and I really liked the concept of a single family tree, so I tried it, but all of the hints that they offered me during my 30-day free trial were for the wrong people. Now, there were some hints that they wouldn't show me without me paying them, even during my free trial, so it may be that those hints (or some of them) were actually accurate, but the fact that all the ones they did show me for free were wrong didn't do anything to convince me to give them my money. (I found the same on Ancestry.) (Besides which, I have a deal with my wife: I'm allowed to pursue genealogy as a hobby, as long as I don't let it turn into an obsession, and the line between "hobby" and "obsession" is whether I spend money on it.)
Then I found WikiTree, and I loved it from the start. I like it that it's really free, rather than offering "free" accounts and then bombarding me with messages to upgrade my nearly-useless free account to a premium account with all the bells and whistles that don't actually work on my free account. I really like it that (eventually) I was able to link my family to the main tree, so I could say that I was only 37 degrees from A.J., or Kevin Bacon, or Her Majesty the Queen. I like it that people care about accuracy in their trees, and are not willing to accept anybody's unverified word for it that they're descended from the Plantagenets or whomever. (Although I will freely admit that that insistence on accuracy in sourcing and everything else has forced me to up my game considerably, and I'm still working on it.)
Tips I picked up here have helped me to push back Dad's genealogy another couple of generations, and have also helped me to fill out other branches of my tree, although I still have a ton of work to do.