I usually use Credit Karma's links when they have the one I want, otherwise I just use the one on the airline's website or email they sent me. If a registered charity had links, I would use those too.
I have Firefox ....... so it would be good if Flyertalk could list their links on a separate page, I wouldn't mind using them as I know the hosting charges must be huge for a site this size.
I don't know why other banks don't do like Amex and give people their own links.