The size limitation on GEDCOM files which could be imported into Geni has been an issue and it looks as if their developers have addressed this.
The old limit of 15,000 records has now been raised to 50,000 records and the press release/email blast from Geni states, "We hope that this will attract many more genealogists to Geni to share their research with their family and collaborate with others."
Curiously this news hasn't yet been posted to the Geni blog or in the Knowledgebase/Help section of Geni itself.
As I've said before in previous posts, to me Geni is the web application that best reproduces the Facebook experience for genealogists and family historians. If you have a chance today, check out Geni.