As excited as I was to start posting content on Google Sites (formerly JotSpot), there are a number of issues / limitations that I think are show-stoppers for now.
However, after working with a number of different wiki products, both free and commercial, Google Sites seems excessively simple, to the point of restrictive. One example is when creating a new page, a type of page must be chosen. There then seems to be no option for changing that page's type, short of deleting it and creating a new one.
Deleting pages, however, is what I see to be one of the biggest issue with the current version of Sites. While a page or attachment can be "deleted", either seems to be infinitely recoverable, with no option to "permanently delete". As discussed in this thread, Steven Hind ("Visionary") wrote:
The ability to recover deleted pages is absolutely necessary as Google Sites allows collaboration, and a collaborator may delete a page (unintentionally or deliberately) and the owner may need to get it back.
While that is definitely a valid use-case, site owners should at least be given the option to permanently purge / remove "deleted" items. There are usability reasons, such as difficulty in recreating pages with the same name. More seriously are the security concerns, e.g. if something accidentally gets posted that shouldn't have been. Granted, even if something disappears from Sites, it may still be obtainable through Google Cache or the Internet Archive: Wayback Machine. However, even these services properly respect robot exclusions.
Working with included page images is a similar but even more mysterious issue. Images inserted into a page without being included "as an attachment" seem to function as "hidden attachments". Even when removed from the page, they remain available for later repeated use, with no visible method of removal.
Searching for "delete page" on the Site's Help returns dozens of results, with many users sharing the same concern. Hopefully this is something Google will address in the near future.
In the meantime, I'm still looking for a decent solution where I can share some of my code and projects, as open source, but under "my control". While I'll continue to use dev.java.net, it's really only purposed for Java projects. I have at least one Microsoft .NET project that I'd like to share. Google Code and SourceForge.net are two other options I explored, but again, leave very little control left with the owner. Especially when built on Subversion, the Subversion Obliterate issue makes it practically impossible to perform a removal when needed.
Update (2008-12-27): I just found this: http://groups.google.com/group/sites-help/web/wishlist. "Ability to permanently delete an uploaded file" is included, but it doesn't mention anything about permanent deletion / removal of pages.