Cruisemates signature area in your profile is limited to 512 characters. Most larger cruise clocks have HTML or BB code that is larger than that. The cruisemates countdown clock will work and some websites have clocks with a limited amt. of code. One other thing, I think cruisemates webmaster has their HTML code area turned off but the BB code is on. Might sound a little technical but really pretty simple. Just follow the directions on the 'clocks' site.