If you plan to try and get it published, I'd say don't do it.
If it's just for fun, and you want to share it with your friends, I'd say go ahead, but remember that internet excerpts should be much shorter than those you'd print out on paper. My (serious) blog entries are running 1500-1750 words, and they're looong. I'm posting my NaNo novel in bits, about a third of a chapter at a time, or 1000 words or less.
ETA: If you do decide to put it up in any form on the 'net, and if, at any point in the future, you think you might like to get paid for writing, make sure that what you put up is as correct as possible with regards to grammar, spelling, and conventional usage. Just because you aren't trying to get paid for this particular piece of writing doesn't mean it can't be used as a writing sample when trying to interest agents, publishers, etc., down the road a bit.
And your readers deserve the best you can give, whether you get paid for it or not.