Yes. Twitter is just a tool. Blame the users not Twitter if it's dull. If people are interested in office supply offers they'll follow Whistle Ink and stop if it's too dull. The same for me and Adwords. My Twitter is a community of people that either provide Adwords services, or are otherwise interested in Adwords/
SEO/Online Sales- it works fine for me.
... and yes some people do follow you in the hope they will be followed. If they spam you then block them. Use Tweetdeck to filter out all the garbage.