What is a blog?
Blogs tend to be websites that have multiple articles and are usually opinion or advice pieces, unlike news articles which are objective reporting (at least they try to be objective).
Blogs will also have pretty charged language, evoking an opinion. For example, a news article might say something like 'Sales for the new phone were in the thousands, which was far below expectations'; a blog might say the same thing like this: 'The new company only sold a mere 1000 phones.'-- the use of the words 'Only' and 'Mere' suggest that the author is conferring judgment and therefore it is an opinion piece.
They will usually have a date and listed author for each article. Example