When this happens I write a post naming the business. Today the business owner contacted me. Amazing how fast my blog gets the information out there! He assured me he wasn't blog spamming anyone and that it was not him. I assured him that it was him and I'd seen this many times before.
He'd approved an SEO organisation to promote his business but hadn't thought that when business acts on his behalf, he has given them authority, so it is indeed his responsibility. Businesses need to ask for details of how their business is to be promoted. The SEO (and I've seen web designers do this as well) then outsource the work. They may not even know what is going to be done. The work gets sent offshore and the blog spamming begins. Hundreds or even thousands of blogs get the comment along the lines "Wow, love your blog and will come back regularly, and by the way here is my site type of comment".
Many small businesses don't have a clue their marketing is hurting their business reputation. Who wants to deal with a business that uses disreputable techniques to promote their business. I certainly wouldn't. There are many very good ethical and honourable businesses people can use. If you find a business hurts your business reputation dump them immediately. Often they'll know what they're doing isn't right but all they are really interested in is your money. It is your business reputation that suffers as no one has a clue who you are using.
The good outcome is this IT business in Queensland is now aware they were blog spamming and is now looking for another SEO business.