There are good sites that when the web master messes up will do that. It's not a sign of a hack.
As to scanning your Apple for malware, etc. Read this before you are tempted by MacKeeper and other bad things:
https://discussions.apple.com/docs/DOC-2435
Bob
My ex - an "ethical hacker" - recently set up my new wifi. I immediately started getting messages that certain web sites wouldn't load because they were going through too many re-routes. (These were sites I'd visited prior to him setting up my new wifi with no issues.) How can I tell if he set up something to intercept my wifi/internet transmissions remotely? More importantly, will simply changing the router name and password help, or do I need to do more? I'm on a Mac, with an "Actiontech" modem/router combo unit.

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