it's true that we all make mistakes (I'm referring to typos)..typing. Some of us use all 10 fingers, some two and some just 1; However the probability of typing errors is pretty high no matter how good we are at the keyboard. When we type something into a document, and make errors, we could ensure the quality of the "text" be excellent as we'd use a spell checker, thesaurus etc. Whichever editor (Microsoft Office, OpenOffice, StarOffice) we use; there always is some kind of a feature whereby we could check the spellings etc. The same goes for creation of web pages and blogs too; However when we comment on other's blogs and are provided with nothing more than a comment box. How many of us type in stuff and validate the "syntax" of each word or run it by spellcheck / thesaurus or the likes...
Some mistakes can turn into blunders. Mis-Spelt words can give a whole new meaning to a statement. There's a spellcheck feature addon for internet explorer called iespell, and NOW there's Rite of Tongue, a addon for Mozilla's FireFox that would validate the spelling for all content within a text box and actually prompt you to correct them; thus ensuring that you say what you mean. 
Right-click on a typed word inside a web form on any webpage to get a suggested spelling for that word. Then select the word from the popup menu to change it. The words are obtained in real-time over the Internet using Yahoo!'s Spelling Suggestion service.
Rite Of Tongue is an extremely cool addon. Just a right-click on the word and the menu will display the correct spelling if known. Just mouse down to select and replace the word being checked. This addon comes extremely handy for those late night owls, beer and pajama junkies, and the starbucks addicts.