If I wasn’t entirely clear, Google’s “site:” operator limits the search only to web pages whose domain name matches whatever you specify after the colon. And like all Google search operators, it can be negated with the minus sign/hyphen. So, f’rexample,
blah1 blah2 blah3 site:www.chowhound.com
will bring return hits on any web pages on Chowhound-the-website that include the terms blah1, blah2, and blah3, while the search
blah1 blah2 blah3 Chowhound
will also return results on sites other than CH if the page happens to mention the word “Chowhound” as well as the other terms.
And as far as the wildcard business is concerned (which I personally use mostly for keeping Pinterest hits out of my lists of results):
will exclude all of the irksomely extensive Pinterest subdomains/variants that end in a single prefix (like the US-based “www.pinterest.com” or Italy’s “www.pinterest.it”, etc)
will exclude the variants that use double-prefixes, like “www.pinterest.co.uk” (among others…)
And last but not least, you can use the operator multiple times in a single search, so you can, for example, do a search that excludes all (or almost all) of the Pinterest stuff by including both terms in the same search. In other words,
blah -site:*.pinterest.*.* -site:*.pinterest.*
will return hits for “blah” anywhere on the Web except a Pinterest site/web page.