There’s an excellent and newly released Firefox addon, called Google Custom Search 1.1.2, made by Kai Londenberg in Germany. It quickly creates independently-hosted anonymous Google Custom Search Engines, which you can then manage and refine directly from buttons embedded in your Google search results. And just like the official Google CSEs, you get cut-and-paste HTML code which lets others use your CSE (without them needing to log in or install anything).

It was only launched in September, so it still has some issues:

* Backing up your CSE as an XML file is currently a little tricky but it is possible.

* Anyone who knows the address of your CSE can potentially grab the XML that defines it, steal it and then surround all your hard work with tacky adverts.

* Making a CSE this way is currently an “add one URL/domain at a time” job, as you surf the search results day in and day out. There’s no initial mass upload of an URL list, as there is in official Google CSEs.

* Search results don’t feature Google’s new “Options…” sidebar, when searching via your -hosted CSE.

* There’s no guarantee that will stay paid-up in the long term

There are advantages, though:

* Very easy to set up a “throwaway” CSE for specific search tasks.

* Anonymity (although not if you foolishly announce it / link to it / host the search-box page under your own name, of course)

* Refinement and tweaking of the engine is integrated right into the search results

* It uses the Google API, and so does most of what the official CSEs do.

* It seems likely that there’s no 5,000 URL limit on a CSE, as there is with official Google CSEs.

* Mass collaborative CSEs seem possible — I’ve emailed the author to ask exactly how this feature works. The documentation is exemplary for a Firefox addon, but it doesn’t explain this aspect.