If you have expertise or a passion or interest for a subject, you're ready to start making money with a blog. With a service like Blogger (www.blogger.com), you can start up your blog totally free. You can also create your own site and secure your own hosting for a low price, which is generally the route I recommend, as many free blogging sites have restrictions on what you can say or do, including making money or advertising.
If you are a software developer of course the internet is your strongest marketing platform. There is a large market for software on the internet. All you need to do is to look for a task in the IT world and then build a software to help simplify the task. For example; you can develop a software that will help people manage their clientele base (CRM software), you can develop software that will help people manage their payrolls, accounts, online files et al.