For those of you who might want to clear your browsing history and cookies in iOS5 on an iphone 4s (can't confirm on any other device--all I have), it does not appear to completely remove browsing data.
For instance, if you were shopping for a present on a website that you didn't want your significant other to see (because that would be the ONLY reason any of us would clear our browsing data, right?), you could clear your history and cookies, but someone could go to Settings --> Safari --> Advanced --> Website Data and see a list of websites you've visited recently, albeit with 0.0 kb of data for each. So, for the truly paranoid, there's a third place you have to clear to remove all traces.
As a side note, I finally solved a problem of double alerts for messages even though I had repeating alerts set to "none." Posted what solved it for me here.
For instance, if you were shopping for a present on a website that you didn't want your significant other to see (because that would be the ONLY reason any of us would clear our browsing data, right?), you could clear your history and cookies, but someone could go to Settings --> Safari --> Advanced --> Website Data and see a list of websites you've visited recently, albeit with 0.0 kb of data for each. So, for the truly paranoid, there's a third place you have to clear to remove all traces.
As a side note, I finally solved a problem of double alerts for messages even though I had repeating alerts set to "none." Posted what solved it for me here.