Totally agree with Robynne. I was interested in adding my data as a gedcom but I put it off long enough to have read up on the process in various helpful files and here in G2G.
In addition to Robynne's answer, I would make a couple of other observations. Gedcoms are allowed but all too often new members upload a large gedcom, realize how much time it will take to manually merge profiles and data, and then abandon the whole thing, and often just never come back to Wikitree. That leaves the cleaning up to volunteers who arealready overwhelmed with making improvements (both gedcom and manually input profiles). Its my understanding that once put on the site, it has to dealt with by someone, it doesn't go away on its own.
The other thing is that, depending on where the gedcom came from or how it was made, a large amount of information coding particular to that genealogy website or program comes through into the new profile. This coding can make the information difficult to understand in many cases. So the uploader has to go over each profile and work the information into formats compatible with those used on Wikitree. And if the uploader actually goes through all of this process, particularly on large files, more time will probably be spent on corrections and formating than if the profiles had been added manually.
One advantage of manual entering is that it gives the Wikitree member a chance to review their information, particularly when adding sources; often times finding typos, incorrect entries and other incorrect entries. In the search for primary sources, one occasionally finds an ancestral link that, while known for generations, has no primary sources to establish the link. This in turn supports the ideal of better research and sources for profiles on Wikitree.
I've been on Wikitree for a couple of years in a few months and I had a huge gedcom. I started helping my mother with our genealogy in the late 1950s, so I have a gedcom of almost 60 years of research, and I chose to enter it manually. I have found it tedious at times, but vastly more rewarding. I know I will never get it all input here, but thats okay. The goal of Wikitree is not the rapidity in which we can amass a huge amount of profiles, but rather in the accuracy and trustworthyness of what is entered.
Okay, I'll come down off my soapbox and say Welcome to Wikitree