A popular writing convention is to use liberally capitalization in headings. I see this blog posts, but I see it on news sites, too.
According to The Canadian Style, published by the Translation Bureau, has this to say on the matter:
In headings that begin at the margin, capitalize only the first word and any other words that require capitals in their own right. In centred headings, capitalize all words except for articles (unless they begin the heading) and any conjunctions or prepositions of fewer than four letters. Prepositions that are an inseparable part of the verb should also be capitalized.
So, for headings in blog posts, capitalizing every word is unnecessary. Just capitalize the first word and leave the rest lowercase.