It's obviously important not to link to sites that are banned by Google in your link partner strategy, which I was already aware of, but never knew exactly how to check. Isn't the grayed Google toolbar gone now? How do others check if each of your link partners is not banned by Google? Is there a sure-fire way?
Well, you can check if their site is indexed by searching for "site:example.com". If they aren't, either they're banned or too new to have been indexed, and in both cases a link partnership with them won't do you much good...
Just enter the URL in the google search box (homepage url). If you get this: * If the URL is valid, try visiting that web page by clicking on the following link: www * Find web pages from the site www * Find web pages that contain the term "www" then the site is not yet properly indexed, will be soon - probably if you get this * Find web pages from the site www * Find web pages that contain the term www site is probably banned. no pages left in the index AND google thinks the url is not invalid (or : valid) so... but I've seen sites that seem to be banned, but still have pagerank, so there's probably not a real 100% check to see if a site is banned, especially with new sites.
Someone else answered this question in another forum and suggested that you check with Whois.com to see how long the site ahs exisited for - that way you can tell if it's old and been banned vs just being brand new.
I guess its way to much time to spend checking it in whois. Willy is right - just check if they're indexed - they wont be in index if they are banned. Also if the page you want your link listed at is in cache - it's a good indication that it's search engine friendly and has a lucid path for bots from higher level pages.