If the worst thing that happens is the college coach hits the 'delete' button, then that is not too bad. Obviously, you don't want to contact every day with the most mundane details and be known as the Stalker Libero.
I would think that if you are sending out a 5 minute video every month, and updating every few weeks with club/high school significant items, then that is a good routine. As you enter into the playing segment of this club season, a quick fyi email out about your tourney attendance and playing schedule is just smart recruiting communication.
The challenge is your position and how late in the recruiting process that college coaches can effectively secure an elite level Libero. You don't want to get ahead of the process, but rather be steady. Staying in the 'conversation' should be your goal - When the college coaches are talking about their Libero/DS needs for the 2014 class, you want them to bring your name up.
As for calling, unless a program you are supremely interested in is aggressive in its outreach/communication, I would hold off. Email communication is easy to manage and engage; you or the coach can let it sit for a day or two. But, a call is much more invasive and that is where you would risk being annoying. Better to wait to engage in calls later in the spring and early summer of this coming club season!
Stay focused, be patient and as hard as you are working on communication/recruiting, work twice as hard on your skills. Unlike the hitters, who coaches put a lot of weight on 'potential' or future ability, the LIberos are judged on 'right now'.