Be careful with those porn URLs. This is not something new, but it hasn't been publicized much AFAIK. There are flaws in various OS regarding automatic registration of "URL handlers". I don't exactly understand it, but somehow a URL can contain a command or direction to operate a program, either remote or on your machine, which can do harm to other files on your machine. Such a URL would have a direction in it, like file: or disk:, that you'd spot if you saw the actual URL, but you won't spot if the URL encloses a website name or other innocent-looking phrase.