I've been seeing intermittent slowdown and complete failures to load since about the middle of last week. Various errors given when it fails to load -- at one point I was briefly even getting a failure to resolve to an IP address (and trying a site to look up IP from hostname failed as well).
Sometimes I will click on one topic, have it load instantly, then within a minute or two another one fails to load (and trying the original it then fails to load as well).