I use tail -f and when I need to search, I use iTerm's search (Cmd+F) which highlights matches and even supports regex. I also have an unlimited scroll buffer so I can just scroll up or down to get the context of a particular match.
This only works if what you are searching for has scrolled past since you started following. If you want to see other occurrences in the file you're out of luck. For example, let's say you are watching to see which error message is generated when something goes wrong, then you want to see when else that error message has been thrown.
That only works if you only care about search results since you started tailing. If you want to search for what happened before you started tailing, you need to stop tailing and use less/grep/etc.
