The Extended File Allocation Table (exFAT), the file-system designed by Microsoft for flash-drives where FAT32 or NTFS isn't ideal, still doesn't have proper Linux support. The last time I talked about Linux support for exFAT was back in 2009 and since then not much has changed.
There was work on a kernel module to provide read-only kernel-level exFAT file-system support natively under Linux, but that's not actively worked on. More pressing though, at this point it doesn't stand chances on being merged into the mainline Linux kernel due to licensing concerns with exFAT being a proprietary Microsoft file-system.
The more appropriate solution for those really after Microsoft exFAT support under Linux is by using an exFAT implementation in user-space with FUSE. Like the ZFS and NTFS support, there's a FUSE module for exFAT.
Hosted on Google Code is a full-featured exFAT file-system implementation built on FUSE, with the same advantages and disadvantages of other FUSE file-systems.
For those very serious about exFAT on Linux, Tuxera -- the same company that claims NTFS is the fastest Linux file-system -- does have exFAT Embedded (product page). This is a legal implementation of exFAT on Linux with Tuxera having gone through the proper licensing channels to receive the file-system documentation and construct this Linux kernel module. Tuxera also offers exFAT for Android devices.