If you aren't using Tumblr to build your blog, your brand and your business... you ARE being left behind.
Fact: Tumblr is quickly surpassing WordPress as the default blog platform for most emerging online entrepreneurs under the age of 25. It's also the absolute EASIEST way to create a community of people who are paying attention to your marketing message, and a community of clients (and CASH) as well.
The ONLY drawback of building your business blog on Tumblr?
It's a closed platform... meaning, rather than posting all of the content on your own web server, and using your own CMS of choice, with Tumblr... everything is baked into their own proprietary process.
(ironically, this is also one of the big ADVANTAGES of using Tumblr to build your blog as well, as there is very little learning curve, it's 100% free and you don't have to do anything other than register an email address to get started)
Personally, i use BOTH WordPress for my primary blog, and Tumblr for my community building blog, and I'm going to be totally honest with you, while I LOVE WordPress for a lot of reasons, for getting INSTANT eyeballs in front of your ideas, (and offers) there is nothing better than a Tumblr blog to go from zero to hero and make it happen in a hurry.
The FASTEST way to get friends and followers on Tumblr?
Very simple. Re-blog other peoples content for 60 minutes a day. Use the tags feature, and simply follow as many keywords as are relevant to your niche, market or industry. (or if you are in a hyper local business and are competing geographically, using geo friendly tags is REALLY effective as well)