I recently changed my hosting and had a problem with one of my domains. I raised a ticket with the host and they fixed it and this is what they said the problem was:
The SecFilter line in your htaccess was causing a 500 error - I've removed it (it's not needed as we don't run mod_security)
Well, whatever they did got the site up OK but now I don't know if it is a good thing or a bad thing that this host does not run mod_security. I have tried reading up on it but it is a bit too techie for me.
If anyone could tell me a bit about it I would be grateful and failing that, on a scale of 1 to 10, how much should I be concerned?