When using Safari, try doing the following:
Right-click the URL in the Address Bar (where it says "forum.celtcsstrong.com"). You should get a context menu.
Choose "Settings for this Website..."
In the options that are presented, choose "Enable content-blockers".
This should (hopefully) stop many of these problems.
I have it in this mode (the default for all my browsing) and the only ad-related glitche that I'm finding annoying is the following:
Every time I go to a thread page, an add banner is placed across the bottom of the page, forcing me to click the "X" to close it. In Safari, which by default has a right scroll bar that only appears ("on demand") when you scroll or move the mouse over to where it will appear, the scroll bar pops up overlaying most (not all) of the ad-banner's close button. I have to very carefully click on the part of the button that is still exposed. Not a huge deal, but annoying.