The SATA standard was originally crafted with mechanical disks in mind, but since the advent of SSDs, a new protocol is being considered necessary specifically for those types of drives. Dubbed Non-Volatile Memory Host Controller, the new protocol is expected to be far more efficient because it is optimized for how SSDs read and write data.
It was initially hoped that NVMHCI would crop up sooner rather than later, but at this point it appears it will be later, with laptop manufacturers and other companies still planning to use the SATA interface in the near-term. Part of the reason may be that NVMHCI support was speculated to appear in Windows 7, but Microsoft has sort of dashed those rumors now.
It's expected to take from 5 to 10 years for the new standard to be fully adopted for use with SSDs, which isn’t really surprising. SATA moved somewhat faster as a successor to PATA but it had the advantage of sharing much in common with PATA, making adoption easier for manufacturers.