Are Blogs a Good Place for Promoting Businesses?

I have been running an internet store for the last two years and I have become very familiar with the art of internet promotion for my wares and how to drive traffice to my site. It seems to me though that over the last few months most blogs, which at first were a nice way to exchange ideas and provide each there own soapbox, are now becoming a spam heaven!

I spend hours on end searching throuh hundreds of spam blogs just to find one of interest. I have no problem with someone trying to get a plug for their site but they should at least try and contribute something of value to the online community.