The bigger problem is that blog posts (usually) don't give you context for their advice. In some cases (eg. trying out a throwaway prototype to determine if Twitter is appropriate for your product), putting Twitter config in a global variable is perfectly appropriate. In others, it'll break production code. Unless the author is very careful to explain the particular situation where he did this and why, it's likely that you'll draw the wrong conclusion for your particular use-case.
Usually, blogs aren't that reliable because it is solely option based.I wouldn't go to blogs if one is researching. It rarely contains other's opinion, plus it is not peer-reviwed. Blogs can be read for entertainment purposes. However, some blogs are reliable if they reference peer-reviwed journals. Knowing that they took that extra step to find credible sources for their blog posts make it more reliable.