For example, if you search for [African countries], Google Squared generates a list of countries, then it finds attributes that should be appropriate when you describe a country (capital, currency, image/map) and it tries to find values for the attributes. Google Squared shows only the first 7 results, but you can always add new results and even new attributes. Clicking on the first blank column, Google Squared suggests 5 new columns: area, religion, language, GDP and Internet users.
A search for [endangered species] returns relevant search results, although Wikipedia has a more comprehensive list.
Google Squared is good at finding palindromes from a lot of sources:
Google Squared's results aren't always great: if you search for [Motown], Google finds relevant artists like Diana Ross or Marvin Gaye, but it mixes them with songs like "Got to be there".
If you find mistakes, Google Squared lets you remove rows, columns, select alternative values for attributes and save the customized square online so you can share it with other people.
The service seems to be a clever combination between Google Sets, which creates sets of items from a few examples, and Google Q&A, which extracts facts from the web (an example: [Britney Spears' mother]). In fact, you can even start with an empty square and dynamically add items and attributes.