A friend of mine who's a data analyst **looks for a platform/site to create** his blog there. Options he expects to be available are posting text (+formatting), pics, maybe animated graphs, code boxes, formulas (in laTex or like), commenting or answering. Something approaching, maybe partly, the options of our site - only as personal journal, in this instance. Free, if possible.

Can you advise some? What are features there? If you have a blog, what are your pros and cons for it (mean, the platform features)?