Many internet marketers have more than one blog and there's nothing wrong with that. Having many streams of income is always a good idea, especially online. It could be that they are following a business model where they put up quick blogs and routinely fill it with content.
These blogs are typically monetized with AdSense and can earn the marketer a few dollars per day. The real income comes from having lots of these blogs where the AdSense earnings can really add up. There are pros and cons to having more than one blog and I'll explore that here.
Time is the biggest negative. It takes time to put up each new blog, and it takes a lot of time to add posts to these sites day in and day out. If you had 50 blogs (and some people do) and wanted to add content even 3 days per week, that would mean 150 blog posts per week!
This is next to impossible unless you're doing really well from them and can afford to hire a content manager to write and post for you. Otherwise, you'll try to keep up the best you can and none of the blogs get the love they deserve. This is stressful, to say the least.
There are automated ways to set these blogs up but the jury is still out regarding SEO and the effectiveness of these blogs in helping you earn the AdSense income.
The more blogs you put up, the more blogging becomes a full time job. One of the things that lured you to internet marketing to begin with was having the freedom to work when and how you wanted. You find you're now employed by your blogs.
You may make more money if you concentrate on a single blog. Add content daily and go out of your way to add value and grow your traffic.
If one blog is making you $5 per day in ads and affiliate promotions, then two blogs could earn you $10 per day. If you have 10 blogs earning that much, you'll make $1500 per month.
If your blogs aren't your personal pride and joys, you can easily populate them with lightly rewritten PLR. If they're WordPress blogs you can set them up to post on a schedule of every other day until the PLR runs out.
Once you have a system down, it's very easy to quickly set up a new blog. It's fun too. As an entrepreneur, you probably come up with fantastic ideas on a daily basis. Take the best of these and create blogs around them.
Blogs are great marketing tools! You can use a blog as a way to communicate with your JV partners before, during, and after a launch. A blog like this can help build anticipation and make you more sales.
You can also use a blog platform for a membership site. The more you work with blogs, the more you'll understand how they can be used with all the available plug-ins.
It's really up to you whether you want to have more than one blog. It depends on your business model and what you're trying to accomplish with the blogs. One suggestion, however, is to wait until your first blog is making money so you can replicate your success over and over.