I normally enter the SDMB through the main SD page (http://www.straightdope.com/). There, I see a banner ad at the top of the page. When one of the ads from PNC is up (“National City is now PNC” etc etc), it somehow prevents the rest of the page from loading, and I get just a blank page with a single banner ad at the top, although the page source still seems to be OK. Reloading the page helps only if a non-PNC ad appears; since 2/3 of the ads seem to be from PNC, it can take 4-5 refreshes before the page appears.
Yes, I can go directly to http://boards.straightdope.com/ and it’s not a big deal, but I would think this is an issue you might want to take care of, since ads shouldn’t be preventing visitors from seeing content.
IE Version 8.0.6001.18904, if if helps.