This single-purpose Firefox extension lets you passively and anonymously share your Google Web Search™ searches on the secure website https://www.searchcopy.ch/.
You can see what other anonymous users are searching for. Likewise other users can see your searches. This passive approach provides a much more detailed and granular view than actively sharing stuff.
For searches that you don't want to share you can disable this extension on the Firefox add-ons page.
You can set a pseudonym and your age in the Firefox add-on preferences for the SearchCopy add-on.