For awhile I would get issues about certificate errors, etc. Today, I could not go to my webmail, check mail nor go to say godaddy.com in Safari, Omniweb nor Mail.app.
After 90 mins of mucking around, deleting corrupted Fonts (now my TextMate font is all messed up, later issue) I found this thread on apple discussions
In short, deleting com.apple.security.revocation.plist from ~/Library/Preferences/ and relaunching Omniweb/Mail cured the problem!