I don't know for sure when the next signature campaign will start but I think it would be when the txbit exchange launches or a couple of weeks before as that gives something for people to promote and gets more exposure ready for when the exchange launches, well that is when I'll be running my next signature campaign if I was the dev, it just makes more sense to run one at that time then now. Or there could be one at the end of March ready for when Solaris goes POS and Zerocoin protocol becomes active.