Last year a teenager sent me an article with a covering email saying:
Sorry, I didn’t have time to proofread it properly. Sure you can sort it out!
Erm, no, I don’t think so. I replied by telling him to re-send it when he had a little more time. I’m still waiting.
Any half-decent word-processor will have a spellchecker and a grammar checker. There may also be a thesaurus, to help you find the best possible word to use in a particular sentence.
But these tools aren’t enough. For example, a spellchecker won’t pick up on homonyms, ie words which sound the same but don’t mean the same, like “deer” and “dear”. Also, the brain has a tendency to insert words into gaps, eg if the word “the” is missing, you may not notice even after several read-throughs. For that reason, it’s always good to ask someone else to read through it as well.
Bottom line: technology can certainly assist you in your blogging and writing activities, but you’d be silly to rely on them 100%!