This is the phase most likely to be forgotten and under-scheduled. It is however, essential that every piece of the project is tested adequately before it is launched.
At this pointall major usability testing has been completed ( we may do some final testing upon which we could make minor changes).
We are now performing quality assurance (QA).
Every element and link must be checked on every page in every browser on every platform, etc. It is detailed, laborious work, but it is essential for creating a professional product.
and
functionality testing (does it work, at volume, on different platforms, browsers)
final usability testing (is it natural and intuitive) - though at this point it may be too late for major changes which is why we do usability testing early in this whole process
cross-platform testing
proofreading
graphic QA (ensuring web production has not created poor images)
code verification
bug-fixes
Deliverables: Final product, maintenance schedule, and all documentation