Yep, I get a variety of the browser hijacking ads here and on f150forums. It's to the point where these two forums are unusable with Chrome on my phone. I thought it might be a malicious app, but after deleting all my apps one by one (to no avail), trying a few different malware apps and eventually doing a factory reset on my phone, the problem is still there.

After some more reading, it seems that it is not a problem with the actual device, but is due to one or more unscrupulous advertisers being allowed to operate on the sites. On other forums that have had the problem, it appears that it wasn't that easy for the adminstrators to figure out which of their advertisers were responsible. Using other ad-blocking mobile browsers, or desktops stops the hijacking, but I prefer Chrome for most things, and only really use desktops/laptops for work. I wish the 24hr administrators would figure out who the responsible advertiser is and give them the boot so the rest of us can use the forum.