Are you behind a proxy server? In Chrome, do you have the Developer toolbar, if so, Toolbar, Information, View Response Headers, what is the Content-type? Fire

Are you behind a proxy server? In Chrome, do you have the Developer toolbar, if so, Toolbar, Information, View Response Headers, what is the Content-type? Firefox has similar tools, HeaderSpy will also do it. If the content type is wrong as you suggested in an earlier post, it would indicate a problem between you and tumblr.com. If the response is valid, it would suggest a problem, perhaps with an extension (though, if it happens across multiple browsers, that is unlikely). curl -I https://www.tumblr.com/ https://www.tumblr.com/ (or some url that has just given you problems) - Is the content type correct on that? Do you have anything in your hosts file that might be overriding their IPs? Disable gzip compression in your browser, try again. I know that some versions of Firefox and Chrome had issues with gzip - preferring deflate and tumblr appears to be sending gzip. Though, those issues were fixed in recent (last few months) versions of both. Also, what IP address or addresses does your machine believe belong to www.tumblr.com?