Acronyms. They make typing easier. And if people recognise the acronym, you could argue that acronyms make reading slightly quicker as well. They also help cut down on typos and spelling mistakes.
Now for the downside. You would be amazed at the level of ignorance people have on different subjects. Put it an other way, people's knowledge sets are quite varied. Worse, if they are tired, in a hurry, stressed, under the influence or sick, that knowledge, and the ability to retrieve it, will also vary.
So here is what I'm getting at: use acronyms and lose your audience. Even popular ones like NAFTA and GTA can draw a blank. Given the poor English skills of many Canadians (for example, French-Canadians, Aboriginals and the 50% of Torontonians who were born in an other country (not exaggerating)), you really do risk losing your audience. And heaven forbid someone is trying to read your blog via Google translate...
So dumb it down at tad. Avoid acronyms, and keep your audience in the loop. With the "find and replace" function, there is no justification for acronyms.
At the very least, use the proper usage (PU) of putting the acronym in parenthesis after you have defined it once. By using the PU readers will have an easier time. But unless extra words mean extra cost, I don't see the point. Just write dam thing, long form (JWDTLF).
By JWDTLFing you will help your readers understand what you are writing, which, for most bloggers, is the whole point.
NAFTA: North American Free Trade Agreement
GTA: Greater Toronto Area