K-5 Bloggers

So far this year our K-5 students have effectively responded to blogs, and I am now really excited and honestly a bit nervous about our next venture-having our K-5 students create blogs. Several educators recommended classblogmeister for the creation K-5 blogs. However, I have contacted the site several times abour receiving a school pass code so we can post there but I haven't received a response. Does anyone have any info about how you obtained a school pass code to classblogmeister or about any other sites that would allow K-5 students to safely create blogs? Thanks so much.