Old thread, but cracked it.

Links with apostrophes (') or encoded apostrophes (%27) are automatically blocked by siteground.

It's a protection against SQL Injection attacks. Nice extra filter there for users running inept software but we're safe, so I'll ask them to disable it.

You will see it if you have a link like (DON'T CLICK THESE, THEY'RE EXAMPLES!!!)://www.debtfreefanatics.com/showthread.php?2497-C-is-for-cookie&highlight=won%27t
or
http://www.debtfreefanatics.com/show...ight=won't

because the apostrophe (encoded or not) can be a precursor to a hacking attempt.

I'm going to ask our host, siteground, to disable the protection.