Currently, your entire tree is exported. A user's privacy settings will control what is exported
To download your GEDCOM file, make sure you are logged in to Geni and click the GEDCOM link in the footer. An email will then be sent to your primary email address with a link that allows you to download your export in a .zip file.
Let us know in the forum whether the file looks and works as you'd expect. We'd also like to hear your concerns with what information you would want to be exportable.
We are aware that many of you are even more interested in importing of GEDCOM files. That is a longer project that involves our tree merging features--we'll keep you updated in this forum as we get closer.
Thank you for using this feature the Geni Team is looking forward to your feedback.  Notes
Sometimes foreign language characters don't seem to export properly. Try opening the file and changing the line that reads CHAR UTF-8 to CHAR ANSEL or CHAR UNICODE and see if that resolves the issue.
PAF treats occupations as attributes, and Geni treats occupations as events. PAF will import the occupation information, but you will see "Unexpected tag 'ADDR' in Event Detail Structure." errors in your import log which can safely be ignored.
Marriages events attended by individual will be emitted under the INDI record for the individual. Some programs ignore this and it appears to cause no problem with importing the rest of the data.