Haha funny you mentioned my name, I just noticed this post and was just going to say I noticed the same.
My stuff has been having intermittent issues too but it's most likely unrelated as I'm on a different host (Carat Networks). One day I kept getting agent down alarms and restorals non stop for a good hour. Turns out the host was having a DDoS attack so it was affecting lot of clients. Could be the same idea though. Next time it happens you could try to pop on your host's support chat if they have that feature and ask if they're getting reports, and if they know what the issue is. But it could be anything really. Maybe even something on the server, but if nothing has changed I'd be more willing to bet it's an external issue.
Also it almost seems to be slow specificity when replying or editing a post, especially editing. This almost points me to believe it may be something more specific to the forum application. Is the SQL server hosted somewhere else? Could be a problem with that host. Certain forum functions call different queries, some are more complicated than others, so it would explain why some stuff is slower than other.
I don't think it's a problem with "the internet" though. I work in a telco CO and "the internet" is in the room not far from my office and when I walked by there the other day all the lights were blinking as they should.
(of course that's just the internet for my city and not actually THE internet.